Defined in header <cstdlib> | ||
|---|---|---|
Defined in header <cmath> | (since C++17) | |
int abs( int n ); | ||
long abs( long n ); | ||
long long abs( long long n ); | (since C++11) | |
Defined in header <cstdlib> | ||
long labs( long n ); | ||
long long llabs( long long n ); | (since C++11) | |
Defined in header <cinttypes> | ||
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) |
| n | - | integer value |
The absolute value of n (i.e. |n|), if it is representable.
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.
#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
| absolute value of a floating point value (|x|) (function) |
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| returns the magnitude of a complex number (function template) |
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applies the function std::abs to each element of valarray (function template) |
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C documentation for abs, labs, llabs |
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