## C++ program to find LCM using a separate function:

In this post, we will learn how to find the *LCM* of two numbers in *C++* by using a separate function. *LCM* is also called *least common multiple*, is the lowest common multiples of two numbers.

It is the *smallest* number which is divisible by both numbers.

Letâ€™s take a look at the programs.

## Find LCM in C++:

```
#include <iostream>
using namespace std;
int findLCM(int firstNumber, int secondNumber)
{
int firstMultiple = firstNumber;
int secondMultiple = secondNumber;
while (firstMultiple != secondMultiple)
{
if (firstMultiple < secondMultiple)
{
firstMultiple += firstNumber;
}
else
{
secondMultiple += secondNumber;
}
}
return firstMultiple;
}
int main()
{
int first, second;
cout << "Enter the first number : " << endl;
cin >> first;
cout << "Enter the second number : " << endl;
cin >> second;
int lcm = findLCM(first, second);
cout << "LCM: " << lcm << endl;
}
```

Here,

- We are reading the numbers as inputs from the user and storing these in
*first*and*second*variables. *findLCM*function is used to find the lcm of two numbers. It takes two*integers*as arguments and returns the*LCM*. This value is stored in the variable*lcm*.- Inside
*findLCM*, we have created two variables*firstMultiple*and*secondMultiple*to keep the multiples of the first and the second number. - The
*while loop*runs until the multiples of both numbers become equal. Inside the loop, we are incrementing the multiple, whichever is the smaller. - Once the loop will end,
*firstMultiple*and*secondMultiple*both will hold equal values. We can return any one of these value.

If you run this program, it will give output as like below:

```
Enter the first number :
11
Enter the second number :
12
LCM: 132
Enter the first number :
9
Enter the second number :
99
LCM: 99
```

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