std::lcm
Defined in header <numeric> |
||
|---|---|---|
template< class M, class N > constexpr std::common_type_t<M, N> lcm( M m, N n ); |
(since C++17) |
Computes the least common multiple of the integers m and n.
Parameters
| m, n | - | integer values |
Return value
If either m or n is zero, returns zero. Otherwise, returns the least common multiple of |m| and |n|.
Remarks
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>.
Exceptions
Throws no exceptions.
Notes
Feature testing macro: __cpp_lib_gcd_lcm.
Example
#include <numeric>
#include <iostream>
#define OUT(...) std::cout << #__VA_ARGS__ << " = " << __VA_ARGS__ << '\n'
constexpr auto lcm(auto x, auto y) {
return std::lcm(x,y);
}
constexpr auto lcm(auto head, auto...tail) {
return std::lcm(head, lcm(tail...));
}
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));
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
See also
|
(C++17)
|
constexpr function template returning the greatest common divisor of two integers (function template) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/numeric/lcm
