std::abs,std::labs,std::llabs,std::imaxabs (3) - Linux Manuals

std::abs,std::labs,std::llabs,std::imaxabs: std::abs,std::labs,std::llabs,std::imaxabs

NAME

std::abs,std::labs,std::llabs,std::imaxabs - std::abs,std::labs,std::llabs,std::imaxabs

Synopsis

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)

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