In this section we will see C Program to find the GCD and LCM of two number by Euclid’s algorithm.

**GCD –** The **greatest common divisor** (**GCD**) of two or more integers, which are not all zero, is the largest positive integer that divides each of the integers.

**LCM –** The **least common multiple (LCM)** of two numbers is the “smallest non-zero common number” which is a multiple of both the numbers.

**For Example :- GCD and LCM of 24 and 40 is 8 and 120**

Now let’s see the C Program to find the GCD and LCM of two number by Euclid’s algorithm

#### C Program

/* Finding GCD and LCM by Euclid's algorithms */ #include <stdio.h> int gcd(int n1, int n2); /* function prototype */ int main(){ int n1, n2; printf("Enter two positive integers: "); scanf("%d%d", &n1, &n2); printf("\nG.C.D of %d and %d is %d.", n1, n2, gcd(n1,n2)); printf("\nL.C.M of %d and %d is %d\n", n1, n2, (n1*n2)/gcd(n1,n2)); return 0; } /* function define as recursion */ int gcd(int n1, int n2){ if (n2 != 0) return gcd(n2, n1%n2); else return n1; }

#### Output :-

#### Conclusion

In this article you have successfully seen how to write a C Program to find the GCD and LCM of two numbers by Euclid’s Method. If you have any doubt then do ask in the comment section.