# How To Compute The Greatest Common Divisor And Least Common Multiple in C++?

The C++ 17 standard brings us a lot of useful methods, templates, numerics, and algorithms. Two of the great numeric functions are `std::gcm` and `std::lcm` which are defined in the <numeric> header that computes the greatest common divisor and least common multiple of two integers. In this post, we learn what `std::gcm` and `std::lcm` are, and how can we use them in modern C++.

## What is std::gcm the greatest common divisor numeric function in C++?

In mathematics, the Greatest Common Divisor (GCD) also known as the Highest Common Factor (HCF) of two integer numbers is the largest number that exactly divides both numbers. In C++, the std::gcm greatest common divisor numeric function is defined in the `<numeric>` header that computes the greatest common divisor of the given two integers.

Here is the syntax of std::gcm since C++17,

Here how we can find the greatest common divisor of two numbers in C++,

this will return 23 because both has 23 divisor which is the greatest one.

## What is the std::lcm least common multiple numeric function in C++?

In mathematics, the Least Common Multiple (LCM) also known as the Lowest Common Multiple, or Smallest Common Multiple of two integer numbers is the lowest common multiple number of two integers In C++, the std::lcm least common multiple numeric function is defined in the `<numeric>` header that computes the lowest multiple number of the given two integers.

Here is the syntax of std::lcm since C++17,

Here how we can find the lowest common multiple, of two numbers in C++,

this will return 12 because 12 is the lowest common multiple of 12 and 6.

## Is there a full example about std::gcm and std::lcm numeric functions in C++?

Here is a full example about std::gcm and std::lcm numeric functions in modern C++,

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