Difference between revisions of "cpp/numeric/lcm"
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Revision as of 05:04, 17 March 2022
| Defined in header <numeric>
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| 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.
Contents |
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-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_gcd_lcm |
Example
Run this code
#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) |
computes the greatest common divisor of two integers (function template) |
