# C Program to Find LCM of a Number using Recursion

«
»

This is a C Program to find lcm of a number using recursion.

Problem Description

This C Program Finds LCM of a Number using Recursion.

Problem Solution

The following C program, using recursion, finds the LCM. An LCM is the lowest common multiple of any 2 numbers.

Program/Source Code

Here is the source code of the C program to find LCM of a Number using Recursion. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```/*
* C Program to Find LCM of a Number using Recursion
*/
#include <stdio.h>

int lcm(int, int);

int main()
{
int a, b, result;
int prime;

printf("Enter two numbers: ");
scanf("%d%d", &a, &b);
result = lcm(a, b);
printf("The LCM of %d and %d is %d\n", a, b, result);
return 0;
}

int lcm(int a, int b)
{
static int common = 1;

if (common % a == 0 && common % b == 0)
{
return common;
}
common++;
lcm(a, b);
return common;
}```
Program Explanation

In this C program, we are reading the two integer numbers using ‘a’ and ‘b’ variables respectively. The lcm() function is used to find LCM of a number using recursion.

Assign the value of ‘common’ variable as 1. If condition statement is used to check the modulus of the value of ‘common’ variable by the value of ‘a’ variable is equal to 0. Also the modulus of the value of ‘common’ variable by the value of ‘b’ variable is equal to 0 using AND operation. If the condition is true, then execute the statement and return the ‘common’ value. Print the LCM of a number using the printf statement.

Runtime Test Cases
```
\$ cc pgm22.c
\$ a.out
Enter two numbers: 456
12
The LCM of 456 and 12 is 456

\$ a.out
Enter two numbers: 45 75
The LCM of 45 and 75 is 225```

Sanfoundry Global Education & Learning Series – 1000 C Programs. 