C Programming Code Examples C > Functions Code Examples C program to find GCD (HCF) of two numbers using recursion C program to find GCD (HCF) of two numbers using recursion Write a recursive function in C to find GCD (HCF) of two numbers. How to find GCD(Greatest Common Divisor) or HCF(Highest Common Factor) of two numbers using recursion in C program. Here in this program we will be using recursive approach of Euclidean algorithm to find GCD of two numbers. The Euclidean algorithm to find GCD is, Algorithm to find GCD using Euclidean algorithm Begin: function gcd(a, b) If (b = 0) then return a End if Else return gcd(b, a mod b); End if End function End #include <stdio.h> /* Function declaration */ int gcd(int a, int b); int main() { int number1, number2, hcf; /* Input two numbers from user */ printf("Enter any two numbers to find GCD: "); scanf("%d%d", &number1, &number2); hcf = gcd(number1, number2); printf("GCD of %d and %d = %d", number1, number2, hcf); return 0; } /* Recursive approach of euclidean algorithm to find GCD of two numbers */ int gcd(int a, int b) { if(b == 0) return a; else return gcd(b, a%b); }
