Difference between revisions of "cpp/numeric/math/abs"
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m (Lolus moved page cpp/numeric/math/abs to Help:My abs) |
Revision as of 11:55, 9 February 2019
| Defined in header <cstdlib>
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| Defined in header <cmath>
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(since C++17) |
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| int abs( int n ); |
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| long abs( long n ); |
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| long long abs( long long n ); |
(since C++11) | |
| Defined in header <cstdlib>
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| long labs( long n ); |
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| long long llabs( long long n ); |
(since C++11) | |
| Defined in header <cinttypes>
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| std::intmax_t abs( std::intmax_t n ); |
(since C++11) | |
| std::intmax_t imaxabs( std::intmax_t n ); |
(since C++11) | |
Computes the absolute value of an integer number. The behavior is undefined if the result cannot be represented by the return type.
If std::abs is called with an argument of type X such that std::is_unsigned<X>::value is true and X cannot be converted to int by integral promotion, the program is ill-formed. |
(since C++17) |
Contents |
Parameters
| n | - | integer value |
Return value
The absolute value of n (i.e. |n|), if it is representable.
Notes
In 2's complement systems, the absolute value of the most-negative value is out of range, e.g. for 32-bit 2's complement type int, INT_MIN is -2147483648, but the would-be result 2147483648 is greater than INT_MAX, which is 2147483647.
Example
Run this code
#include <iostream> #include <cstdlib> #include <climits> int main() { std::cout << "abs(+3) = " << std::abs(3) << '\n' << "abs(-3) = " << std::abs(-3) << '\n'; // std::cout << std::abs(INT_MIN); // undefined behavior on 2's complement systems }
Output:
abs(+3) = 3 abs(-3) = 3
See also
| (C++11)(C++11) |
absolute value of a floating point value (|x|) (function) |
| returns the magnitude of a complex number (function template) | |
| applies the function abs to each element of valarray (function template) | |
| C documentation for abs, labs, llabs
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