Programming Ruby
The Pragmatic Programmer's Guide
class Bignum
Parent:
Integer
Version:
1.6
Index:
Arithmetic operations
Bit operations
<=>
[ ]
size
to_f
to_i
to_s
Bignum objects hold integers outside the range of
Fixnum.
Bignum objects are created automatically when
integer calculations would otherwise overflow a
Fixnum. When a
calculation involving
Bignum objects returns a result that will
fit in a
Fixnum, the result is automatically converted.
For the purposes of the bitwise operations and
[], a
Bignum is treated as if it were an infinite-length bitstring
with 2's complement representation.
While
Fixnum values are immediate,
Bignum objects are
not---assignment and parameter passing work with references to
objects, not the objects themselves.
instance methods
Performs various arithmetic operations on
big.
big
+
aNumeric
Addition
big
--
aNumeric
Subtraction
big
*
aNumeric
Multiplication
big
/
aNumeric
Division
big
%
aNumeric
Modulo
big
**
aNumeric
Exponentiation
Performs various operations on the binary
representations of the
Bignum.
~ big
Invert bits
big
|
aNumeric
Bitwise OR
big
&
aNumeric
Bitwise AND
big
^
aNumeric
Bitwise EXCLUSIVE OR
big
<<
aNumeric
Left-shift aNumeric bits
big
>>
aNumeric
Right-shift aNumeric bits
(with sign extension)
<=>
big <=>
aNumeric -> -1, 0, +1
Comparison---Returns -1, 0, or +1 depending on
whether
big is less
than, equal to, or greater than
aNumeric. This is the
basis for the tests in
Comparable.
Bit Reference---Returns the
nth bit in
the (assumed) binary representation of
big,
where
big[0] is the least significant bit.
a = 9**15
50.downto(0) do |n|
print a[n]
end
produces:
000101110110100000111000011110010100111100010111001
size
big.size ->
anInteger
Returns the number of bytes in the machine representation
of
big.
(256**10 - 1).size
サ
12
(256**20 - 1).size
サ
20
(256**40 - 1).size
サ
40
Converts
big to a
Float. If
big doesn't fit in a
Float, the result is infinity.
Returns
big.
Returns a string containing the decimal representation of
big.
Extracted from the book "Programming Ruby -
The Pragmatic Programmer's Guide"
Copyright
©
2001 by Addison Wesley Longman, Inc. This material may
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