Min standard

std::gcd

Since C++17

Header: <numeric>

Computes the greatest common divisor of the integers m and n.

# Declarations

template< class M, class N >
constexpr std::common_type_t<M, N> gcd( M m, N n );

(since C++17)

# Parameters

m, n: integer values

# Return value

If both m and n are zero, returns zero. Otherwise, returns the greatest common divisor of |m| and |n|.

# Notes

Feature-test macro Value Std Feature __cpp_lib_gcd_lcm 201606L (C++17) std::gcd, std::lcm

# Example

#include <numeric>
 
int main()
{
    constexpr int p{2 * 2 * 3};
    constexpr int q{2 * 3 * 3};
    static_assert(2 * 3 == std::gcd(p, q));
 
    static_assert(std::gcd( 6,  10) == 2);
    static_assert(std::gcd( 6, -10) == 2);
    static_assert(std::gcd(-6, -10) == 2);
 
    static_assert(std::gcd( 24, 0) == 24);
    static_assert(std::gcd(-24, 0) == 24);
}

# See also

lcm