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 .
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 > .
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 | .
Exceptions
Throws no exceptions.
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_gcd_lcm
|
201606L | (C++17) |
std::gcd
,
std::lcm
|
Example
#include <iostream> #include <numeric> #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
See also
|
(C++17)
|
computes the greatest common divisor of two integers
(function template) |