std::gcd

Defined in header `<numeric>`
template< class M, class N > constexpr std::common_type_t<M, N> gcd( M m, N n );		(since C++17)

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

m, n

integer values

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

If either M or N is not an integer type, or if either is (possibly cv-qualified) bool, the program is ill-formed.

If either |m| or |n| is not representable as a value of type std::common_type_t<M, N>, the behavior is undefined.

Throws no exceptions.

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