Library: Input/output
Predefined stream that controls output to a stream buffer associated with the object stdout declared in <cstdio>
#include <iostream>
namespace std {
extern ostream cout;
}
The object cout controls output to a stream buffer associated with the object stdout declared in <cstdio>. By default the standard C and C++ streams are synchronized, but performance improvement can be achieved by using the ios_base member function synch_with_stdio to desynchronize them.
After the object cin is initialized, cin.tie() returns &cout, which implies that cin and cout are synchronized.
The formatting is done through member functions or manipulators.
showpos
setf(ios_base::showpos)
noshowpos
unsetf(ios_base::showpos)
showbase
setf(ios_base::showbase)
noshowbase
unsetf(ios_base::showbase)
uppercase
setf(ios_base::uppercase)
nouppercase
unsetf(ios_base::uppercase)
showpoint
setf(ios_base::showpoint)
noshowpoint
unsetf(ios_base::showpoint)
boolalpha
setf(ios_base::boolalpha)
noboolalpha
unsetf(ios_base::boolalpha)
unitbuf
setf(ios_base::unitbuf)
nounitbuf
unsetf(ios_base::unitbuf)
internal
setf(ios_base::internal,
ios_base::adjustfield)
left
setf(ios_base::left,
ios_base::adjustfield)
right
setf(ios_base::right,
ios_base::adjustfield)
dec
setf(ios_base::dec,
ios_base::basefield)
hex
setf(ios_base::hex,
ios_base::basefield)
oct
setf(ios_base::oct,
ios_base::basefield)
fixed
setf(ios_base::fixed,
ios_base::floatfield)
scientific
setf(ios_base::scientific,
ios_base::floatfield)
resetiosflags
(ios_base::fmtflags flag)
setf(0,flag)
setiosflags
(ios_base::fmtflags flag)
setf(flag)
setbase(int base)
see above
setfill(char_type c)
fill(c)
setprecision(int n)
precision(n)
setw(int n)
width(n)
endl
ends
flush
flush( )
showpos
Generates a + sign in non-negative generated numeric output.
showbase
Generates a prefix indicating the numeric base of generated integer output
uppercase
Replaces certain lowercase letters with their uppercase equivalents in generated output
showpoint
Generates a decimal-point character unconditionally in generated floating-point output
boolalpha
Inserts and extracts bool type in alphabetic format
unitbuf
Flushes output after each output operation
internal
Adds fill characters at a designated internal point in certain generated output. If no such point is designated, it's identical to right.
left
Adds fill characters on the right (final positions) of certain generated output
right
Adds fill characters on the left (initial positions) of certain generated output
dec
Converts integer input or generates integer output in decimal base
hex
Converts integer input or generates integer output in hexadecimal base
oct
Converts integer input or generates integer output in octal base
fixed
Generates floating-point output in fixed-point notation
scientific
Generates floating-point output in scientific notation
resetiosflags(ios_base::fmtflags flag)
Resets the fmtflags field flag
setiosflags(ios_base::fmtflags flag)
Sets up the flag flag
setbase(int base)
Converts integer input or generates integer output in base base. The parameter base can be 8, 10 or 16.
setfill(char_type c)
Sets the character used to pad (fill) an output conversion to the specified field width
setprecision(int n)
Sets the precision (number of digits after the decimal point) to generate on certain output conversions
setw(int n)
Sets the field width (number of characters) to generate on certain output conversions
endl
Inserts a newline character into the output sequence and flushes the output buffer
ends
Inserts a null character into the output sequence
flush
Flushes the output buffer
precision() 6 width() 0 fill() the space character flags() skipws | dec getloc() locale::locale()
Keep in mind that while the manipulator endl flushes the stream buffer, outputting the character '\n' is not guaranteed to flush the stream buffer. You should output the '\n' character without endl only if you do not need the buffer flushed. Note that outputting the '\n' character in such cases, and hence not forcing a buffer flush, may result in a performance improvement. It greatly improves performance when C and C++ streams are not synchronized.
basic_ostream, basic_iostream, basic_filebuf, cin, cerr, clog, wcin, wcout, wcerr, wclog
ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Section 27.3.1