std::lcm - cppreference.com (original) (raw)

Computes the least common multiple of the integers 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.

The behavior is undefined if |m|, |n|, or the least common multiple of |m| and |n| is not representable as a value of type std::common_type_t<M, N>.

[edit] Parameters

[edit] Return value

If either m or n is zero, returns zero. Otherwise, returns the least common multiple of |m| and |n|.

[edit] Exceptions

Throws no exceptions.

[edit] Notes

[edit] Example

#include #include   #define OUT(...) std::cout << #VA_ARGS << " = " << VA_ARGS << '\n'   constexpr auto lcm(auto x, auto... xs) { return ((x = std::lcm(x, xs)), ...); }   int main() { constexpr int p{2 * 2 * 3}; constexpr int q{2 * 3 * 3}; static_assert(2 * 2 * 3 * 3 == std::lcm(p, q)); static_assert(225 == std::lcm(45, 75));   static_assert(std::lcm( 6, 10) == 30); static_assert(std::lcm( 6, -10) == 30); static_assert(std::lcm(-6, -10) == 30);   static_assert(std::lcm( 24, 0) == 0); static_assert(std::lcm(-24, 0) == 0);   OUT(lcm(2 * 3, 3 * 4, 4 * 5)); OUT(lcm(2 * 3 * 4, 3 * 4 * 5, 4 * 5 * 6)); OUT(lcm(2 * 3 * 4, 3 * 4 * 5, 4 * 5 * 6, 5 * 6 * 7)); }

Output:

lcm(2 * 3, 3 * 4, 4 * 5) = 60 lcm(2 * 3 * 4, 3 * 4 * 5, 4 * 5 * 6) = 120 lcm(2 * 3 * 4, 3 * 4 * 5, 4 * 5 * 6, 5 * 6 * 7) = 840

[edit] See also

| | computes the greatest common divisor of two integers (function template) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |