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### Program to Find LCM of Two Numbers - C, C++ Code

Write a program to find LCM of two numbers in C, C++. Given two numbers a and b, we have to write a code to find LCM of a and b.

In this tutorial, we cover following topics.

• What is LCM?
• Program to find LCM of two numbers in C++
• Program to find LCM of two numbers in C

## What is LCM (Least Common Multiple)?

The LCM of two numbers is the smallest number that is divisible by both numbers.

For example -

LCM(8, 16) - Least common multiple of 8 and 16 is 16.

Multiples of 8 are :

8, 16, 24, 32 .......

Multiples of 16 are :

16, 32, 48, 64 .......

Common multiples of 8 and 16 are :

16, 32, 64 ..........

So, the least common multiple (LCM) of 8 and 16 are 16.

Formula to calculate LCM(a, b) = (a * b) / GCD(a, b)

In my previous post, i have already discussed and explained the program to find GCD of two numbers using Recursion.

## Program to Find LCM of Two Numbers in C++

```#include <iostream>
using namespace std;

int gcd(int a, int b) {

if(b == 0){
return a;
}

return gcd(b , a%b);
}

int lcm(int a, int b) {

return (a*b)/gcd(a, b);
}

int main() {

int a, b, result;

// Input
cout << "Enter two numbers \n";
cin  >> a >> b;

// Method call to calculate LCM
result = lcm(a, b);

cout << " LCM of " << a << " and " << b << " is " << result;
return 0;
}
```

## Program to Find LCM of Two Numbers in C

```#include <stdio.h>

int gcd(int a, int b) {

if(b == 0){
return a;
}

return gcd(b , a%b);
}

int lcm(int a, int b) {

return (a*b)/gcd(a, b);
}

int main() {

int a, b, result;

printf("Enter two numbers \n");
scanf( "%d%d", &a, &b);

result = lcm(a, b);

printf("LCM of %d and %d is %d", a, b, result);

return 0;
}

```

Output :

Enter two numbers :   3,   5

LCM of 3 and 5 is  15