C program to find LCM and GCD using recursion of two integers entered by the user.
Please go through following C programming articles to understand the concept of the program.
We have use following formula to find the LCM of two numbers using GCD
LCM = (number1 * number2) / GCD
Visit this page to learn how to calculate GCD using loops
C program to find GCD and LCM using recursion
#include <stdio.h>
int gcd(int x, int y); //function prototype
int main()
{
int num1, num2, hcf, lcm;
printf("Enter two integer Values:\n");
scanf("%d %d", &num1, &num2);
hcf = gcd(num1, num2);
printf("GCD: %d", hcf);
printf("\nLCM: %d", (num1 * num2) / hcf);
return 0;
}
//recursive function
int gcd(int x, int y)
{
if (y == 0) //recursion termination condition
{
return x;
}
else
{
return gcd(y, x % y); //calls itself
}
}
Output
Visit this page to learn how to calculate LCM using loops
Explanation
In the above program, recursive function gcd returns the value of gcd. The termination condition of the recursive function is y == 0 which checks whether the number is equal to zero or not.