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<h1><a name="math">math.h</a> </h1> <tr> <a href="#fpclassify">fpclassify</a> classify floating point type <tr> <a href="#isfinite">isfinite</a> test for finite <tr> <a href="#isfinite">isinf</a> test for infinity <tr> <a href="#isfinite">isnan</a> test for NaN <tr> <a href="#isfinite">isnormal</a> test for normal <tr> <a href="#signbit">signbit</a> test sign bit of floating point value <tr> <a href="#acos">acos</a> arc cosine <tr> <a href="#asin">asin</a> arc sine <tr> <a href="#atan">atan</a> arc tangent <tr> <a href="#atan2">atan2</a> arc tangent in 4 quadrants <tr> <a href="#ceil">ceil</a> round upwards <tr> <a href="#cos">cos</a> cosine <tr> <a href="#cosh">cosh</a> hyperbolic cosine <tr> <a href="#cbrt">cbrt</a> cube root <tr> <a href="#exp">exp</a> e<sup>x</sup> <tr> <a href="#exp2">exp2</a> 2<sup>x</sup> <tr> <a href="#expm1">expm1</a> e<sup>x</sup> - 1 <tr> <a href="#fabs">fabs</a> absolute value <tr> <a href="#floor">floor</a> round downwards <tr> <a href="#fmod">fmod</a> remainder after division <tr> <a href="#frexp">frexp</a> extract exponent and mantissa <tr> <a href="#hypot">hypot</a> hypotenuse <tr> <a href="#ilogb">ilogb</a> logarithm base 2 <tr> <a href="#ldexp">ldexp</a> n*2<sup>exp</sup> <tr> <a href="#log">log</a> natural logarithm <tr> <a href="#log2">log2</a> base-2 logarithm <tr> <a href="#logb">logb</a> logarithm base 2 <tr> <a href="#log10">log10</a> logarithm base 10 <tr> <a href="#log1p">log1p, log1pf</a> natural logarithm of (1 + x) <tr> <a href="#matherr">matherr, _matherrl</a> handle errors generated by math functions <tr> <a href="#modf">modf</a> separate value into integral and fractional parts <tr> <a href="#nextafter">nextafter</a> next representable value <tr> <a href="#poly">poly</a> compute polynomial <tr> <a href="#pow">pow</a> x<sup>y</sup> <tr> <a href="#sin">sin</a> sine <tr> <a href="#sinh">sinh</a> hyperbolic sine <tr> <a href="#sqrt">sqrt</a> square root <tr> <a href="#tan">tan</a> tangent <tr> <a href="#tanh">tanh</a> hyperbolic tangent <tr> <a href="#_cabs">_cabs</a> absolute value of complex number <hr> <h2><a name="fpclassify">fpclassify</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>int fpclassify(x); </tt></dd> <dt><strong>Description</strong></dt> <dd> This function, implemented as a macro, determines if a floating point value belongs to a special class. <em>x</em>'s type is either float, double or long double. The following values can be compared to the result from fpclassify. They classify floating point values and expand to a unique constant expression of type int:<p> <table class="structure"> <th>Value <th>Meaning <tr> <td><strong>FP_NANS</strong> <td>Signalling NaN <tr> <td><strong>FP_NANQ</strong> <td>Quiet NaN <tr> <td><strong>FP_NAN</strong> <td>Quiet NaN (same as FP_NANQ) <tr> <td><strong>FP_INFINITE</strong> <td>Infinity <tr> <td><strong>FP_NORMAL</strong> <td>A number not covered by other classifications <tr> <td><strong>FP_SUBNORMAL</strong> <td>Subnormal or denormal <tr> <td><strong>FP_ZERO</strong> <td>Zero <tr> <td><strong>FP_EMPTY</strong> <td>No value <tr> <td><strong>FP_UNSUPPORTED</strong> <td>Unsupported bit pattern </table> </dd> <dt><strong>Return Value</strong></dt> <dd> Returns a constant that reflects the class of the floating-point expression <em>x</em>. </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd> <a href="#isfinite">isfinite</a> <a href="#isfinite">isinf</a> <a href="#isfinite">isnan</a> <a href="#isfinite">isnormal</a> </dd> </dl> <hr> <h2><a name="isfinite">isfinite, isinf, isnan, isnormal</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>int <strong>isfinite</strong>(x);<br> int <strong>isinf</strong>(x);<br> int <strong>isnan</strong>(x);<br> int <strong>isnormal</strong>(x);<br> </tt></dd> <dt><strong>Description</strong></dt> <dd> Each of these takes an argument of type float, double, or long double; and determines if the argument's value is of the classified type. <p> <table class="structure"> <th>Function <th>Test <tr> <td><strong>isfinite</strong> <td>is normal, subnormal or zero <tr> <td><strong>isinf</strong> <td>is infinity <tr> <td><strong>isnan</strong> <td>is a NaN <tr> <td><strong>isnormal</strong> <td>is not zero, infinity, subnormal, or NaN </table> </dd> <dt><strong>Return Value</strong></dt> <dd> Returns non-zero if a match, 0 if not. </dd> <dt><strong>Compatibility</strong></dt> <dd> C99 7.12.3 </dd> <dt><strong>See Also</strong></dt> <dd> <a href="#fpclassify">fpclassify</a> </dd> </dl> <hr> <h2><a name="signbit">signbit</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>int <strong>signbit</strong>(x); </tt></dd> <dt><strong>Description</strong></dt> <dd> Examines the sign bit of the floating-point value <em>x</em> (including NaNs, infinities, and zero). <strong>signbit</strong> is implemented as a macro, and <em>x</em> can be a float, double or long double. </dd> <dt><strong>Return Value</strong></dt> <dd>Non-zero if the sign bit is 1; zero if the sign bit is 0. </dd> <dt><strong>Compatibility</strong></dt> <dd>C99 7.12.3.6 </dd> </dl> <hr> <h2><a name="acos">acos</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h,<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double <strong>acos</strong>(double x);<br> float <strong>acosf</strong>(float x);<br> long double <strong>acosl</strong>(long double x);<br> </tt></dd> <dt><strong>Description</strong></dt> <dd> The acos functions calculate the principal value of the arc cosine of <em>x</em>. </dd> <dt><strong>Return Value</strong></dt> <dd>The arc cosine of <em>x</em>. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <th><em>x</em> <th>return value <th>invalid? <tr> <td> >1.0 <td> NAN <td> yes <tr> <td> <-1.0 <td> NAN <td> yes <tr> <td> NAN <td> NAN <td> yes </table> </dd> <dt><strong>Compatibility</strong></dt> <dd> DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#asin">asin</a>, <a href="#atan">atan</a>, <a href="#atan2">atan2</a>, <a href="#cos">cos</a>, <a href="#cosh">cosh</a>, <a href="#hypot">hypot</a>, <a href="#sin">sin</a>, <a href="#sinh">sinh</a>, <a href="#tan">tan</a>, <a href="#tanh">tanh</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of acos */ #include <math.h> #include <stdio.h> #include <stdlib.h> void main() { double d; double result; printf("Enter a double:"); scanf("%lg", &d); result = <strong>acos</strong>(d); printf("\nacos(%lg) = %lg\n", d, result); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double:. 45 acos(0.45) = 1.10403 </pre> </dd> </dl> <hr> <h2><a name="asin">asin</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> errno.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double asin(double x);<br> float asinf(float x);<br> long double asinl(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd> The asin functions calculate the principal value of the arcsine of x. asin calculates the arcsine of a double value; asinf calculates the arcsine of a floating-point value; and asinl calculates the arcsine of a long double value. The value of x must be between -1 and 1. </dd> <dt><strong>Return Value</strong></dt> <dd>The arcsine of x. Each function returns a value ranging from -π/2 to π/2. For asinl, if the x argument is outside the range of -1 to 1, the function returns NAN (not a number) and <strong>errno</strong> is set to EDOM, for domain error. </dd> <dt><strong>Special Results</strong></dt> <dd><table class="structure"><tr><th>x</th> <th>return value</th> <th>invalid?</th></tr> <tr><td>±0.0</td> <td>±0.0</td> <td>no</td></tr> <tr><td>>1.0</td> <td>NAN</td> <td>yes</td></tr> <tr><td><-1.0</td> <td>NAN</td> <td>yes</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#acos">acos</a> <a href="#atan">atan</a> <a href="#atan2">atan2</a> <a href="#cos">cos</a> <a href="#cosh">cosh</a> <a href="#hypot">hypot</a> <a href="#sin">sin</a> <a href="#sinh">sinh</a> <a href="#tan">tan</a> <a href="#tanh">tanh Functions </a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of asin */ #include <math.h> #include <stdio.h> #include <stdlib.h> void main() { double d; printf("Enter a double : "); scanf("%lg", &d); printf("\nasin(%g) = %g\n", d,<strong>asin</strong>(d)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double :. 45 asin(0.45) = 0.466765 </pre> </dd> </dl> <hr> <h2><a name="atan">atan</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double atan(double x);<br> float atanf(float x);<br> long double atanl(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The atan functions calculate the arc tangent of x. </dd> <dt><strong>Return Value</strong></dt> <dd>The arc tangent of x. This is a value in the range of -π/2 to π/2. </dd> <dt><strong>Special Results</strong></dt> <dd><table class="structure"><tr><th>x</th> <th>return value</th> <th>invalid?</th></tr> <tr><td>±0.0</td> <td>±0.0</td> <td>no</td></tr> <tr><td>±INFINITY</td> <td>NAN</td> <td>yes</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#acos">acos</a> <a href="#asin">asin</a> <a href="#atan2">atan2</a> <a href="#cos">cos</a> <a href="#cosh">cosh</a> <a href="#hypot">hypot</a> <a href="#sin">sin</a> <a href="#sinh">sinh</a> <a href="#tan">tan</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of atan */ #include <math.h> #include <stdio.h> #include <stdlib.h> void main() { double d; printf("Enter a double : "); scanf("%lg", &d); printf("\natan(%g) = %g\n", d,atan(d)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double :. 45 atan(0.45) = 0.422854 </pre> </dd> </dl> <hr> <h2><a name="atan2">atan2</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double atan2(double y, double x);<br> float atan2f(float y, float x);<br> long double atan2l(long double y, long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The atan2 functions calculate the arc tangent of <em>y/x</em>. </dd> <dt><strong>Return Value</strong></dt> <dd>The arc tangent of <em>y/x</em>. This is a value in the range -π to π. If one argument is a NaN, that NaN is returned; if both arguments are NaNs, either one may be returned. <p> If both arguments are 0, these functions set <strong>errno</strong> to EDOM, print a _DOMAIN error message to stderr, and return 0. </dd> <dt><strong>Special Results</strong></dt> <dd><table class="structure"><tr><th>y</th> <th>x</th> <th>return value</th></tr> <tr><td>±0.0</td> <td> > 0.0</td> <td> ±0.0</td></tr> <tr><td>±0.0</td> <td> ±0.0</td> <td> ±0.0</td></tr> <tr><td>±0.0</td> <td> < 0.0</td> <td> ±π</td></tr> <tr><td>±0.0</td> <td> -0.0</td> <td> ±π</td></tr> <tr><td>> 0.0</td> <td> ±0.0</td> <td> π/2</td></tr> <tr><td>< 0.0</td> <td> ±0.0</td> <td> π/2</td></tr> <tr><td>> 0.0</td> <td> INFINITY</td> <td> ±0.0</td></tr> <tr><td>±INFINITY</td> <td> anything</td> <td> ±π/2</td></tr> <tr><td>> 0.0</td> <td> -INFINITY</td> <td> ±π</td></tr> <tr><td>±INFINITY</td> <td> INFINITY</td> <td> ±π/4</td></tr> <tr><td>±INFINITY</td> <td> -INFINITY</td> <td> ±3π/4</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#acos">acos</a> <a href="#asin">asin</a> <a href="#atan">atan</a> <a href="#atan2">atan2</a> <a href="#cos">cos</a> <a href="#cosh">cosh</a> <a href="#hypot">hypot</a> <a href="#sin">sin</a> <a href="#sinh">sinh</a> <a href="#tan">tan</a> <a href="#tanh">tanh</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of atan2 */ #include <math.h> #include <stdio.h> #include <stdlib.h> void main() { double d1, d2; printf("Enter two doubles : "); scanf("%lg %lg", &d1, &d2); printf("\natan2(%g, %g) = %g\n", d1,d2,<strong>atan2</strong>(d1,d2)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter two doubles :. 3 .4 atan2(0.3, 0.4) = 0.643501 </pre> </dd> </dl> <hr> <h2><a name="cbrt">cbrt</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double <strong>cbrt</strong>(double <em>x</em>);<br> float <strong>cbrtf</strong>(float <em>x</em>);<br> long double <strong>cbrtl</strong>(long double <em>x</em>); </tt></dd> <dt><strong>Description</strong></dt> <dd>The <strong>cbrt</strong> functions calculate the cube root of <em>x</em>. </dd> <dt><strong>Return Value</strong></dt> <dd> The cube root of <em>x</em>. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th> <em>x</em> <th> return value <th> invalid? <tr> <td> ±0.0 <td> ±0.0 <td> no <tr> <td> NAN <td> NAN <td> yes <tr> <td> ±∞ <td> ±∞ <td> no </table> </dd> <dt><strong>Compatibility</strong></dt> <dd> C99 DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd> <a href="#exp">exp</a> <a href="#expml">expml</a> <a href="#pow">pow</a> <a href="#sqrt">sqrt</a> </dd> </dl> <hr> <h2><a name="ceil">ceil</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double ceil(double x);<br> float ceilf(float x);<br> long double ceill(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>Returns the value of x rounded upward to the next integer (toward positive infinity.) </dd> <dt><strong>Return Value</strong></dt> <dd>x rounded up to the next integer. </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#floor">floor</a> <a href="#nearbyint">nearbyint</a> <a href="#rint">rint</a> <a href="#rndtol">rndtol</a> <a href="#rndtonl">rndtonl</a> <a href="#round">round</a> <a href="#trunc">trunc</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for ceil */ #include <math.h> #include <stdio.h> #include <stdlib.h> void main() { double d; printf("Enter a double: "); scanf("%lg",& d); printf("\nCeil (%lg) = %lg\n", d,<strong>ceil</strong>(d)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 3.34 Ceil (3.34) = 4 </pre> </dd> </dl> <hr> <h2><a name="cos">cos</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double cos(double x);<br> float cosf(float x);<br> double cosl(double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The cos functions calculate the cosine of x (measured in radians). </dd> <dt><strong>Return Value</strong></dt> <dd>The cosine of x. If an error occurs because x is too large, <strong>errno</strong> is set to ERANGE. </dd> <dt><strong>Special Results</strong></dt> <dd><table class="structure"><tr><th>x</th> <th>return value</th> <th>invalid?</th></tr> <tr><td>±INFINITY</td> <td>NAN</td> <td>yes</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#acos">acos</a> <a href="#asin">asin</a> <a href="#sin">sin</a> <a href="#cosh">cosh</a> </dd> </dl> <hr> <h2><a name="cosh">cosh</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double <strong>cosh</strong>(double <em>x</em>);<br> float <strong>coshf</strong>(float <em>x</em>);<br> long double <strong>coshl</strong>(long double <em>x</em>); </tt></dd> <dt><strong>Description</strong></dt> <dd>The <strong>cosh</strong> functions calculate the hyperbolic cosine of <em>x</em>. </dd> <dt><strong>Return Value</strong></dt> <dd> The hyperbolic sine of <em>x</em>. If the value of <em>x</em> is too large, <strong>errno</strong> is set to ERANGE. </dd> <dt><strong>Special Results</strong></dt> <dd><table class="structure"><tr><th>value of <em>x</em></th> <th>return value</th> <th>invalid?</th></tr> <tr><td>±INFINITY</td> <td>±0.0</td> <td>no</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#sinh">sinh</a> <a href="#cos">cos</a> </dd> </dl> <hr> <h2><a name="exp">exp</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double <strong>exp</strong>(double x);<br> float <strong>expf</strong>(float x);<br> long double <strong>expl</strong>(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The <strong>exp</strong> functions calculate the value of the natural logarithm base (e) raised to the power of x. </dd> <dt><strong>Return Value</strong></dt> <dd> The value of e<sup>x</sup>. Otherwise, on overflow, returns <strong>HUGE_VAL</strong> and sets <strong>errno</strong> to <strong>ERANGE</strong>. On underflow, returns 0. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th>x <th>return value <tr> <td>+∞ <td>+∞ <tr> <td>-∞ <td>+0.0 </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>C99 DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#exp2">exp2</a> <a href="#expm1">expm1</a> <a href="#log">log</a> <a href="#log1p">log1p</a> <a href="#log10">log10</a> <a href="#pow">pow</a> <a href="#sqrt">sqrt</a> </dd> <dt><strong>Example</strong></dt> <dd> <pre>/* Example of exp */ #include <math.h> #include <stdio.h> #include <stdlib.h> int main() { double d; double result; printf("Enter a double:"); scanf("%lg", &d); result = <strong>exp</strong>(d); printf("\nexp(%lg) = %lg\n", d,result); return 0; } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 2.34 exp(2.34) = 10.3812 </pre> </dd> </dl> <hr> <h2><a name="exp2">exp2</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double <strong>exp2</strong>(double x);<br> float <strong>exp2f</strong>(float x);<br> long double <strong>exp2l</strong>(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd> The <strong>exp2</strong> functions calculate the value of 2 raised to the power of x. </dd> <dt><strong>Return Value</strong></dt> <dd> The value of 2<sup>x</sup>. Otherwise, on overflow, returns <strong>HUGE_VAL</strong> and sets <strong>errno</strong> to <strong>ERANGE</strong>. On underflow, returns 0. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th>x <th>return value <tr> <td>+∞ <td>+∞ <tr> <td>-∞ <td>+0.0 </table> </dd> <dt><strong>Compatibility</strong></dt> <dd> C99 DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#exp">exp</a> <a href="#expm1">expm1</a> <a href="#log">log</a> <a href="#log1p">log1p</a> <a href="#log10">log10</a> <a href="#pow">pow</a> <a href="#sqrt">sqrt</a> </dd> </dl> <hr> <h2><a name="expm1">expm1</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double expm1(double x);<br> float expm1f(float x);<br> long double expm1l(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd> Calculates the value of the natural logarithm base (e) raised to the power of x, minus 1. For very small x, expm1(x) is more accurate than exp(x) -1. </dd> <dt><strong>Return Value</strong></dt> <dd>The value of e<sup><em>x</em></sup>-1 </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th><em>x</em> <th>e<sup><em>x</em></sup>-1 <tr> <td>±0.0 <td>±0.0 <tr> <td>+∞ <td>+∞ <tr> <td>-∞ <td>-1.0 </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#exp">exp</a> <a href="#log">log</a> <a href="#log1p">log1p</a> <a href="#log10">log10</a> <a href="#pow">pow</a> <a href="#sqrt">sqrt</a> </dd> </dl> <hr> <h2><a name="fabs">fabs</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double fabs(double x);<br> float fabsf(float x);<br> long double fabsl(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The fabs, fabsf, and fabsl functions calculate the absolute value of floating-point number <em>x</em>. </dd> <dt><strong>Return Value</strong></dt> <dd>The absolute value of x. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th><em>x</em> <th>return value <tr> <td> ±0.0 <td> +0.0 <tr> <td> ±∞ <td> +∞ </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="/index.cgi/contrast/https://digitalmars.com/rtl/stdlib.html#abs">abs</a> <a href="#copysign">copysign</a> <a href="#signbit">signbit</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of fabs */ #include <math.h> #include <stdio.h> #include <stdlib.h> void main() { double d; double result; printf("Enter a double:"); scanf("%lg", &d); result = fabs(d); printf("\nfabs(%lg) = %lg\n", d,result); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double:-2.34 fabs(-2.34) = 2.34 </pre> </dd> </dl> <hr> <h2><a name="floor">floor</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double floor(double x);<br> float floorf(float x);<br> long double floorl(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>Returns the value of x rounded down to the nearest integer. </dd> <dt><strong>Return Value</strong></dt> <dd> A floating-point value that represents x rounded down to the nearest integer. </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#ceil">ceil</a> <a href="#nearbyint">nearbyint</a> <a href="/index.cgi/contrast/https://digitalmars.com/rtl/fltpnt.html#rint">rint</a> <a href="#rndtol">rndtol</a> <a href="#rndtonl">rndtonl</a> <a href="#round">round</a> <a href="#trunc">trunc</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of floor */ #include <stdlib.h> #include <stdio.h> #include <math.h> void main() { double d; printf("Enter a double: "); scanf("%lg", &d); printf("\nfloor(%g)=%g\n", d,floor(d)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 3.14 floor(3.14)= 3 </pre> </dd> </dl> <hr> <h2><a name="fmod">fmod</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double fmod(double x, double y);<br> float fmodf(float x, float y);<br> long double fmodl(long double x, long double y); </tt></dd> <dt><strong>Description</strong></dt> <dd>These functions calculate the floating-point remainder of x/y. </dd> <dt><strong>Return Value</strong></dt> <dd>The value of x - i * y, where i is the number of times that y can be completely subtracted from x. The result has the same sign as x. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"><tr><th>x</th> <th>y</th> <th>return value</th> <th>invalid?</th></tr> <tr><td>±0.0</td> <td>not 0.0</td> <td>±0.0</td> <td>no</td></tr> <tr><td>±INFINITY</td> <td>anything</td> <td>NAN</td> <td>yes</td></tr> <tr><td>anything</td> <td>±0.0</td> <td>NAN</td> <td>yes</td></tr> <tr><td>!=±INFINITY</td> <td>±INFINITY</td> <td>x</td> <td>no</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd> DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#div">div</a> <a href="#ldiv">ldiv</a> <a href="#remainder">remainder</a> <a href="#remquo">remquo</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for fmod */ #include <stdio.h> #include <stdlib.h> #include <math.h> void main() { double d1, d2, r; printf("Enter two doubles: "); scanf("%lg %lg", &d1, &d2); r = fmod(d1, d2); printf("fmod(%g, %g)=%g\n", d1,d2,r); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter two doubles: 16 7 fmod (16, 7)=2 </pre> </dd> </dl> <hr> <h2><a name="frexp">frexp</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double frexp(double x, int *exp);<br> float frexpf(float x, int *exp);<br> long double frexpl(long double x, int *exp); </tt></dd> <dt><strong>Description</strong></dt> <dd>The frexp, frexpf, _frexpl, and frexpl functions break a floating-point number (x) into a mantisa (m) and an exponent (n), such that 0.5 <= |m| < 1.0 and x = m * 2<sup>n</sup>. The integer exponent n is stored at the location pointed to by exp. </dd> <dt><strong>Return Value</strong></dt> <dd>These functions return the mantissa. If x is 0, the functions return 0 for both the mantissa and the exponent. There is no error return. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"><tr><th>x</th> <th>return value</th> <th>*exp after?</th></tr> <tr><td>±0.0</td> <td> ±0.0</td> <td> +0.0</td></tr> <tr><td>±INFINITY</td> <td>±INFINITY</td> <td> ?</td></tr> <tr><td>NAN</td> <td> NAN</td> <td>?</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#ldexp">ldexp</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for frexp */ #include <stdio.h> #include <stdio.h> #include <math.h> void main() { int e; double d, r; printf("Enter a double: "); scanf("%lg", &d); r = frexp (d, &e); printf("%g, = %g * 2^%d.\n", d,r,e); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 102 102, = 0.796875 * 2^7. </pre> </dd> </dl> <hr> <h2><a name="hypot">hypot</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>float hypotf(float x, float y);<br> double hypot(double x, double y);<br> long double hypotl(long double x, long double y); </tt></dd> <dt><strong>Description</strong></dt> <dd>The hypot functions calculate the length of the hypotenuse of a right-angled triangle with sides of length x and y. The hypotenuse is the value of the square root of the sums of the squares of x and y: <pre>sqrt(x<sup>2</sup> + y<sup>2</sup>) </pre> </dd> <dt><strong>Return Value</strong></dt> <dd> The hypotenuse of a right-angled triangle with sides x and y. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th><em>x</em> <th><em>y</em> <th>return value <th>invalid? <tr> <td><em>x</em> <td>+-0.0 <td>fabs(<em>x</em>) <td>no <tr> <td>+-∞ <td><em>y</em> <td>+∞ <td>no <tr> <td>+-∞ <td>NAN <td>+∞ <td>no </table> <p> Note that hypot(x,y), hypot(y,x) and hypot(x,-y) are equivalent. </dd> <dt><strong>Compatibility</strong></dt> <dd>ANSI C99, DOS, Windows 3.x, Phar Lap, DOSX, Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#cosh">cosh</a> <a href="#sinh">sinh</a> <a href="#tanh">tanh</a> ANSI C99 7.12.7.3, F.9.4.3 </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for hypot */ #include <stdio.h> #include <math.h> void main() { double d1, d2; printf("Enter two doubles: "); scanf("%Lg %Lg", &d1, &d2); printf("\nhypot (%g, %g) = %g\n", d1,d2, hypot (d1, d2)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter two doubles: 5 5 hypot (5, 5) = 7.07107 </pre> </dd> </dl> <hr> <h2><a name="ilogb">ilogb</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>int <strong>ilogb</strong>(double <em>x</em>);<br> int <strong>ilogbf</strong>(float <em>x</em>);<br> int <strong>ilogbl</strong>(long double <em>x</em>); </tt></dd> <dt><strong>Description</strong></dt> <dd>Extracts the exponent of <em>x</em> as a signed integral value. If <em>x</em> is not a special value, the result is the same as if <a href="#logb">logb</a> was called instead and the result was cast to <tt>int</tt>. </dd> <dt><strong>Return Value</strong></dt> <dd> The signed exponent of the argument. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th><em>x</em> <th>Return value <th>Range error? <tr> <td> 0 <td> FP_ILOGB0 <td> yes <tr> <td> ±∞ <td> +∞<td> no <tr> <td> NAN <td> FP_ILOGBNAN <td> no </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>C99 7.12.6.5, Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#logb">logb</a> <a href="#loglp">loglp</a> <a href="#logpf">logpf</a> <a href="#log10">log10</a> <a href="#log">log</a> </dd> </dl> <hr> <h2><a name="ldexp">ldexp</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double ldexp(double n, int exp);<br> float ldexpf(float n, int exp);<br> long double ldexpl(long double n, int exp); </tt></dd> <dt><strong>Description</strong></dt> <dd>Each function uses the following form to multiply a number by an integral power of two:<p> n * 2<sup>exp</sup> </dd> <dt><strong>Return Value</strong></dt> <dd>The value of n * 2<sup>exp</sup>. </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#frexp">frexp</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for ldexp */ #include <stdlib.h> #include <stdio.h> #include <math.h> void main() { int e; double d, r; printf("Enter a double and an int: "); scanf("%lg %d", &d, &e); r = ldexp (d, e); printf("%g = %g * 2^%d.\n\n",r,d,e); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double and an int: 125 5 4000 = 125 * 2^ 5. </pre> </dd> </dl> <hr> <h2><a name="log">log</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double <strong>log</strong>(double <em>x</em>);<br> float <strong>logf</strong>(float <em>x</em>);<br> long double <strong>logl</strong>(long double <em>x</em>); </tt></dd> <dt><strong>Description</strong></dt> <dd>The log functions calculate the natural logarithm of <em>x</em>. </dd> <dt><strong>Return Value</strong></dt> <dd> The natural logarithm of <em>x</em>. If <em>x</em> < 0, a domain error is returned. If <em>x</em> == 0, a range error is returned. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th>value of <em>x</em> <th>return value <th>divide by 0? <th>invalid? <tr> <td>±0.0 <td>-∞ <td>yes <td>no <tr> <td>< 0.0 <td>NAN <td>no <td>yes <tr> <td>+∞ <td>+∞ <td>no <td>no </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#loglp">loglp</a> <a href="#logpf">logpf</a> <a href="#log10">log10</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for log */ #include <stdlib.h> #include <stdio.h> #include <math.h> void main() { double d; printf("Enter a double: "); scanf("%lg", &d); printf("\n<strong>log</strong>(%g)=%g\n\n",d,<strong>log</strong>(d)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 234 log(234)= 5.45532 </pre> </dd> </dl> <hr> <h2><a name="log2">log2</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double <strong>log2</strong>(double <em>x</em>);<br> float <strong>log2f</strong>(float <em>x</em>);<br> long double <strong>log2l</strong>(long double <em>x</em>); </tt></dd> <dt><strong>Description</strong></dt> <dd>The log2 functions calculate the base-2 logarithm of <em>x</em>, log<sub>2</sub><em>x</em>. </dd> <dt><strong>Return Value</strong></dt> <dd> The natural logarithm of <em>x</em>. If <em>x</em> < 0, a domain error is returned. If <em>x</em> == 0, a range error is returned. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th>value of <em>x</em> <th>return value <th>divide by 0? <th>invalid? <tr> <td> ±0.0 <td>-∞ <td>yes <td>no <tr> <td>< 0.0 <td>NAN <td>no <td>yes <tr> <td>+∞ <td>+∞ <td>no <td>no </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>C99 Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#loglp">loglp</a> <a href="#logpf">logpf</a> <a href="#log10">log10</a> <a href="#log">log</a> </dd> </dl> <hr> <h2><a name="logb">logb</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double <strong>logb</strong>(double <em>x</em>);<br> float <strong>logbf</strong>(float <em>x</em>);<br> long double <strong>logbl</strong>(long double <em>x</em>); </tt></dd> <dt><strong>Description</strong></dt> <dd>Extracts the exponent of <em>x</em> as a signed integral value. If <em>x</em> is subnormal, it is treated as if it were normalized. For a positive, finite <em>x</em>: <pre>1 <= <em>x</em> * FLT_RADIX<sup>-logb(<em>x</em>)</sup> < FLT_RADIX </pre> </dd> <dt><strong>Return Value</strong></dt> <dd> The signed exponent of the argument. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th><em>x</em> <th>Return value <th>Divide by 0? <tr> <td> ±∞ <td> +∞ <td> no <tr> <td> ±0.0 <td> -∞ <td> yes </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>C99 Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#ilogb">ilogb</a> <a href="#loglp">loglp</a> <a href="#logpf">logpf</a> <a href="#log10">log10</a> <a href="#log">log</a> </dd> </dl> <hr> <h2><a name="log10">log10</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double log10(double x);<br> float log10f(float x);<br> long double log10l(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The log10 functions calculate the base-10 logarithm of x. </dd> <dt><strong>Return Value</strong></dt> <dd> The base-10 logarithm of x. If x < 0, a domain error is returned. If x == 0, a range error is returned. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th>value of x <th>return value <th>divide by 0? <th>invalid? <tr> <td>±0.0 <td>-∞ <td>yes <td>no <tr> <td>< 0.0 <td>NAN <td>no <td>yes <tr> <td>+∞ <td>+∞ <td>no <td>no </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#log">log</a> <a href="#log1p">log1p</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for log10 */ #include <stdlib.h> #include <stdio.h> #include <math.h> int main() { double d; printf("Enter a double: "); scanf("%lg", &d); printf("\nlog10(%g)=%g\n\n",d,<strong>log10</strong>(d)); return 0; } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 234 log10(234)= 2.36922 </pre> </dd> </dl> <hr> <h2><a name="log1p">log1p, log1pf</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double log1p(double x);<br> float log1pf(float x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The log1p and log1pf functions calculate the natural logarithm of 1 + x. For very small x, log1p(x) will be more accurate than log(1 + x). </dd> <dt><strong>Return Value</strong></dt> <dd> The natural logarithm of 1 + x. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th><em>x</em> <th>log1p(<em>x</em>) <th>divide by 0? <th>invalid? <tr> <td>±0.0 <td>±0.0 <td>no <td>no <tr> <td>-1.0 <td>-∞ <td>yes <td>no <tr> <td><-1.0 <td>NAN <td>no <td>yes <tr> <td>+∞ <td>-∞ <td>no <td>no </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#log">log</a> <a href="#log10">log10</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for log1p */ #include <stdlib.h> #include <stdio.h> #include <math.h> void main() { double d; printf("Enter a double: "); scanf("%lg", &d); printf("\nlog1p(%g)=%g\n\n", d,log1p(d)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 1.234 log1p(1.234)= 0.803794 </pre> </dd> </dl> <hr> <h2><a name="matherr">matherr, _matherrl</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>int matherr(struct exception *except);<br> int _matherrl(struct _exceptionl *except); </tt></dd> <dt><strong>Description</strong></dt> <dd>The matherr and _matherrl functions process errors that have been generated by math functions. The math functions call a math error function whenever an error occurs. Users can also provide their own math error functions to implement special error handling. The _matherrl is called for errors in long double math.<p> A pointer to the exception structure will be passed to a user-supplied math error function when an error occurs. The exception structures, _exception and _exceptionl are defined in math.h. They have the following elements:<p> <table class="structure"><tr><th>Element</th> <th>Description</th></tr> <tr><td>int type</td> <td>Exception type (see the following table)</td></tr> <tr><td>char *name</td> <td>Function name where error occurred</td></tr> <tr><td>double arg1</td> <td>arg2, Function arguments</td></tr> <tr><td>double retval</td> <td>Value returned by function</td></tr> </table> The values for type are:<p> <table class="structure"><tr><th>Value</th> <th>Description</th></tr> <tr><td>_DOMAIN</td> <td>Argument domain error</td></tr> <tr><td>_SING</td> <td>Argument singularity</td></tr> <tr><td>_OVERFLOW</td> <td>Overflow range error</td></tr> <tr><td>_PLOSS</td> <td>Partial loss of significance</td></tr> <tr><td>_TLOSS</td> <td>Total loss of significance</td></tr> <tr><td>_UNDERFLOW</td> <td>Underflow range error</td></tr> </table> </dd> <dt><strong>Return Value</strong></dt> <dd>These functions return 0 to indicate an error, non-zero for success. </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd>The other math functions </dd> </dl> <hr> <h2><a name="modf">modf</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double modf(double x, double *iptr);<br> float modff(float x, float *iptr);<br> long double modfl(long double x, long double *iptr); </tt></dd> <dt><strong>Description</strong></dt> <dd>The modf functions break x into its integral and fraction parts. each of which has the same sign as x. The integral portion is stored in the double pointed to by iptr. </dd> <dt><strong>Return Value</strong></dt> <dd>The signed fractional portion of x. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"><tr><th>x</th> <th>return value</th> <th>*iptr after</th></tr> <tr><td>±INFINITY</td> <td>±0.0</td> <td>±INFINITY</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for modf */ #include <stdlib.h> #include <stdio.h> #include <math.h> void main() { double d, frac, intr; printf("Enter a double: "); scanf("%lg", &d); frac = modf (d, &intr); printf("\nFor %g, the fractional part is" "%g,\nand the integral part is " "%g.\n", d, frac, intr); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 123.456 For 123.456, the fractional part is 0.456, and the integral part is 123. </pre> </dd> </dl> <hr> <h2><a name="nextafter">nextafter</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>fltpnt.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double nextafter(double x, double y);<br> float nextafterf(float x, float y)<br> long double nextafterl(long double x, long double y); </tt></dd> <dt><strong>Description</strong></dt> <dd>Calculates the next representable value after x in the direction of y. </dd> <dt><strong>Return Value</strong></dt> <dd>If y is greater than x, the result will be the next largest floating-point value; if y is less than x, the result will be the next smallest value. If x and y are equal, the result is x. The FE_INEXACT and FE_OVERFLOW exceptions will be raised if x is finite and the function result is infinite. The FE_INEXACT and FE_UNDERFLOW exceptions will be raised if the function value is subnormal, and x is not equal to y. </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for nextafter */ #include <stdio.h> #include <stdlib.h> #include <math.h> #include <fltpnt.h> void main() { double d1, d2, r; printf("Enter two doubles: "); scanf("%lg %lg", &d1, &d2); r = nextafter(d1, d2); printf("nextafter(%g, %g)=%.16f\n", d1, d2, r); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter two doubles: 1 2 nextafter(1, 2)= 1.0000000000000002 </pre> </dd> </dl> <hr> <h2><a name="poly">poly</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double poly(double x, int deg, double coeff[]);<br> long double polyl(long double x, int deg, long double coeff[]); </tt></dd> <dt><strong>Description</strong></dt> <dd>poly and polyl evaluate a polynomial of the form:<p> (coeff[deg] * x + coeff [deg-1]) * x +...+ coeff[0]. <p> Argument x is the base value; deg is the maximum degree, and coeff is an array containing the coefficients of the values. <p> The polyl function is the long double version of poly. </dd> <dt><strong>Return Value</strong></dt> <dd>Both functions return the calculated value of the polynomial. </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for poly */ #include <stdio.h> #include <stdlib.h> #include <math.h> void main() { double coeff[4], x = 1.2, y; coeff[0] = 0.0; coeff[1] = 1.0; coeff[2] = 2.0; coeff[3] = 3.0; y = poly(x, 3, coeff); printf("poly(%g, 3, {%g, %g, %g, %g}) = %g\n", x, coeff[0], coeff[1], coeff[2], coeff[3], y); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>poly(1.2, 3, {0, 1, 2, 3}) = 9.264 </pre> </dd> </dl> <hr> <h2><a name="pow">pow</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double pow(double x, double y);<br> float powf(float x, float y);<br> long double powl(long double x, long double y); </tt></dd> <dt><strong>Description</strong></dt> <dd>The pow functions calculate <em>x</em><sup><em>y</em></sup>. </dd> <dt><strong>Return Value</strong></dt> <dd> x raised to the power of y. If an overflow occurs, the pow functions set <strong>errno</strong> to ERANGE and return _HUGE_VAL or _LHUGE_VAL (if the return type is long double). </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"><tr><th>x</th> <th>y</th> <th>return value</th> <th>div 0</th> <th>inv</th></tr> <tr><td>anything</td> <td>±0.0</td> <td>1.0</td> <td>no</td> <td>no</td></tr> <tr><td>|x| > 1</td> <td>+INFINITY</td> <td>+INFINITY</td> <td>no</td> <td>no</td></tr> <tr><td>|x| < 1</td> <td>+INFINITY</td> <td>+0.0</td> <td>no</td> <td>no</td></tr> <tr><td>|x| > 1</td> <td>-INFINITY</td> <td>+0.0</td> <td>no</td> <td>no</td></tr> <tr><td>|x| < 1</td> <td>-INFINITY</td> <td>+INFINITY</td> <td>no</td> <td>no</td></tr> <tr><td>+INFINITY</td> <td>y > 0.0</td> <td>+INFINITY</td> <td>no</td> <td>no</td></tr> <tr><td>+INFINITY</td> <td>y < 0.0</td> <td>+0.0</td> <td>no</td> <td>no</td></tr> <tr><td>-INFINITY</td> <td>odd integer>0.0</td> <td>-INFINITY</td> <td>no</td> <td>no</td></tr> <tr><td>-INFINITY</td> <td>>0.0, not odd integer</td> <td>+INFINITY</td> <td>no</td> <td>no</td></tr> <tr><td>-INFINITY</td> <td>odd integer<0.0</td> <td>-0.0</td> <td>no</td> <td>no</td></tr> <tr><td>-INFINITY</td> <td><0.0, not odd integer</td> <td>+0.0</td> <td>no</td> <td>no</td></tr> <tr><td>±1.0</td> <td>±INFINITY</td> <td>NAN</td> <td>no</td> <td>yes</td></tr> <tr><td><0.0</td> <td>finite, nonintegral</td> <td>NAN</td> <td>no</td> <td>yes</td></tr> <tr><td>±0.0</td> <td>odd integer <0.0</td> <td>±INFINITY</td> <td>yes</td> <td>no</td></tr> <tr><td>±0.0</td> <td><0.0, not odd integer</td> <td> +INFINITY</td> <td>yes</td> <td>no</td></tr> <tr><td>±0.0</td> <td>odd integer>0.0</td> <td>±0.0</td> <td>no</td> <td>no</td></tr> <tr><td>±0.0</td> <td>>0.0, not odd integer</td> <td> +0.0</td> <td>no</td> <td>no</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#exp">exp</a> <a href="#log">log</a> <a href="#log1p">log1p</a> <a href="#log10">log10</a> <a href="#sqrt">sqrt</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for pow */ #include <stdlib.h> #include <stdio.h> #include <math.h> void main() { double d1, d2; printf("Enter two doubles: "); scanf("%lg %lg", &d1, &d2); printf("\npow(%g, %g)=%g\n", d1, d2, pow (d1, d2)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter two doubles: 2 16 pow(2, 16)= 65536 </pre> </dd> </dl> <hr> <h2><a name="sin">sin</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double sin(double x);<br> float sinf(float x);<br> long double sinl(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The sin functions calculate the sine of x (measured in radians). </dd> <dt><strong>Return Value</strong></dt> <dd>The sine of x. If an error occurs because x is too large, <strong>errno</strong> is set to ERANGE. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"><tr><th>x</th> <th>return value</th> <th>invalid?</th></tr> <tr><td>±0.0</td> <td> ±0.0</td> <td>no</td></tr> <tr><td>±INFINITY</td> <td> NAN</td> <td>yes</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#acos">acos</a> <a href="#asin">asin</a> <a href="#cos">cos</a> <a href="#sinh">sinh</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of sin() */ #include <stdlib.h> #include <stdio.h> #include <math.h> void main() { double d; printf("Enter a double: "); scanf("%lg", &d); printf("\nsin(%g)=%g\n", d, sin(d)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 100 sin(100)=-0.506366 </pre> </dd> </dl> <hr> <h2><a name="sinh">sinh</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double <strong>sinh</strong>(double x);<br> float <strong>sinhf</strong>(float x);<br> long double <strong>sinhl</strong>(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The <strong>sinh</strong> functions calculate the hyperbolic sine of <em>x</em>. </dd> <dt><strong>Return Value</strong></dt> <dd> The hyperbolic sine of <em>x</em>. If the value of <em>x</em> is too large, <strong>errno</strong> is set to <strong>ERANGE</strong>. </dd> <dt><strong>Special Results</strong></dt> <dd> <p> <table class="structure"> <th> <em>x</em> <th> return value <th> invalid? <tr> <td> ±0.0 <td> ±0.0 <td> no <tr> <td> ±∞ <td> ±∞ <td> no </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#cosh">cosh</a> <a href="#sin">sin</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of sinh */ #include <stdlib.h> #include <stdio.h> #include <math.h> void main() { double d; printf("Enter a double: "); scanf("%lg", &d); printf("\nsinh(%g)=%g\n", d, sinh (d)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 12 sinh(12)= 81377.4 </pre> </dd> </dl> <hr> <h2><a name="sqrt">sqrt</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double <strong>sqrt</strong>(double <em>x</em>);<br> float <strong>sqrtf</strong>(float <em>x</em>);<br> long double <strong>sqrtl</strong>(long double <em>x</em>); </tt></dd> <dt><strong>Description</strong></dt> <dd>The <strong>sqrt</strong> functions calculate the square root of <em>x</em>. </dd> <dt><strong>Return Value</strong></dt> <dd> The square root of <em>x</em>. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"> <tr> <th> <em>x</em> <th> return value <th> invalid? <tr> <td> 0.0 <td> 0.0 <td> no <tr> <td> <0.0 <td> NAN <td> yes <tr> <td> NAN <td> NAN <td> yes <tr> <td> +∞ <td> +∞ <td> no </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>C99 DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#exp">exp</a> <a href="#expml">expml</a> <a href="#pow">pow</a> <a href="#cbrt">cbrt</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of sqrt */ #include <stdlib.h> #include <stdio.h> #include <math.h> int main() { double d; printf("Enter a double: "); scanf("%lg", &d); printf("\nsqrt(%g)=%g\n", d, <strong>sqrt</strong>(d)); return 0; } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 81 sqrt(81)= 9 </pre> </dd> </dl> <hr> <h2><a name="tan">tan</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h<br> fltenv.h (Required for exception values) </dd> <dt><strong>Prototype</strong></dt> <dd><tt>double tan(double x);<br> float tanf(float x);<br> long double tanl(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The tan functions calculate the tangent of x (measured in radians). </dd> <dt><strong>Return Value</strong></dt> <dd> The tangent of x.<p> If x is too large, a partial loss of significance may occur. In this case, the tan functions set global variable <strong>errno</strong> to ERANGE and generate a _PLOSS error. If x is so large that significance is totally lost, tan functions print a _TLOSS error message to stderr, set <strong>errno</strong> to ERANGE, and return 0. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"><tr><th>x</th> <th>return value</th> <th>invalid?</th></tr> <tr><td>±0.0</td> <td> ±0.0</td> <td> no</td></tr> <tr><td>±INFINITY</td> <td> NAN</td> <td> yes</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#acos">acos</a> <a href="#tanh">tanh</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of tan */ #include <stdlib.h> #include <stdio.h> #include <math.h> void main() { double d; printf("Enter a double: "); scanf("%lg", &d); printf("\ntan(%g)=%g\n", d, tan(d)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 100 tan(100)=-0.587214 </pre> </dd> </dl> <hr> <h2><a name="tanh">tanh</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double tanh(double x);<br> float tanhf(float x);<br> long double tanhl(long double x); </tt></dd> <dt><strong>Description</strong></dt> <dd>The tanh functions calculate the hyperbolic tangent of x. </dd> <dt><strong>Return Value</strong></dt> <dd> The hyperbolic tangent of x. </dd> <dt><strong>Special Results</strong></dt> <dd> <table class="structure"><tr><th>x</th> <th>return value</th> <th>invalid?</th></tr> <tr><td>±0.0</td> <td> ±0.0</td> <td> no</td></tr> <tr><td>±INFINITY</td> <td> ±1.0</td> <td> no</td></tr> </table> </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="#acos">acos</a> <a href="#tan">tan</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example of tanh */ #include <stdlib.h> #include <stdio.h> #include <math.h> void main() { double d; printf("Enter a double: "); scanf("%lg", &d); printf("\ntanh(%g)=%g\n", d, tanh(d)); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>Enter a double: 3 tanh(3)= 0.995055 </pre> </dd> </dl> <hr> <h2><a name="_cabs">_cabs, _cabsl</a> </h2><dl> <dt><strong>Header</strong></dt> <dd>math.h</dd> <dt><strong>Prototype</strong></dt> <dd><tt>double _cabs(struct _complex z);<br> long double _cabsl(struct _complexl z); </tt></dd> <dt><strong>Description</strong></dt> <dd>The _cabs and _cabsl functions calculate the absolute value of the complex number stored in the z structure. This structure is composed of a real component x and an imaginary component y. In the _cabs function, x and y are double values; in the _cabsl function, x and y are long double values. </dd> <dt><strong>Return Value</strong></dt> <dd>The absolute value of z. If an overflow occurs, these functions return HUGE_VAL, and set variable <strong>errno</strong> to ERANGE. </dd> <dt><strong>Compatibility</strong></dt> <dd>DOS Windows 3.x Phar Lap DOSX Win32 </dd> <dt><strong>See Also</strong></dt> <dd><a href="/index.cgi/contrast/https://digitalmars.com/rtl/stdlib.html#abs">abs</a> <a href="#fabs">fabs</a> </dd> <dt><strong>Example</strong></dt> <dd><pre>/* Example for cabs */ #include <math.h> #include <stdio.h> #include <stdlib.h> void main() { struct _complex z; double retval; z.x = 3.0; z.y = 1.0; retval = _cabs(z); printf("cabs of (%g,%gi) = %g", z.x, z.y, retval); } </pre> </dd> <dt><strong>Output</strong></dt> <dd><pre>cabs of (3,1i) = 3.16228 </pre> </dd> </dl> </div> <div id="footernav"> <a href="https://www.digitalmars.com/" title="digitalmars.com">Home</a> | <a href="/index.cgi/contrast/https://digitalmars.com/rtl/../ctg/ctg.html" title="Compiler and Tools Guide">Compiler & Tools</a> | <a href="/index.cgi/contrast/https://digitalmars.com/rtl/../ugr/ugr.html" title="IDDE Reference">IDDE Reference</a> | <a href="/index.cgi/contrast/https://digitalmars.com/rtl/../stl/index.html" title="Standard Template Library">STL</a> | <a href="https://www.digitalmars.com/advancedsearch.html" title="Search Digital Mars web site">Search</a> | <a href="https://www.digitalmars.com//download/freecompiler.html" title="download C++">Download</a> | <a href="https://www.digitalmars.com/NewsGroup.html" title="Forums">Forums</a> </div> <div id="copyright"> Copyright © 1999-2018 by Digital Mars ®, All Rights Reserved | Page generated by <a href="https://dlang.org/spec/ddoc.html">Ddoc</a>. </div> </div><div class="naked_ctrl"> <form action="/index.cgi/contrast" method="get" name="gate"> <p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="https://digitalmars.com/rtl/math.html">(->オリジナル)</a> / <label>アドレス: <input type="text" name="naked_post_url" value="https://digitalmars.com/rtl/math.html" size="22" /></label> <label>モード: <select name="naked_post_mode"> <option value="default">デフォルト</option> <option value="speech">音声ブラウザ</option> <option value="ruby">ルビ付き</option> <option value="contrast" selected="selected">配色反転</option> <option value="larger-text">文字拡大</option> <option value="mobile">モバイル</option> </select> <input type="submit" value="表示" /> </p> </form> </div> </body> </html>