C program uses recursion to find G.C.D (greatest common divisor)

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In this example, you will learn to find the GCD (greatest common divisor) of two positive integers entered by the user using recursion.

To understand this example, you should understand the followingC programming languageTopic:

• C function

• C user-defined function

• C recursion

Visit this page to learn howUsing a loop to calculate GCD.

Using recursion to calculate the greatest common divisor (GCD) of two numbers

#include <stdio.h>
int hcf(int n1, int n2);
int main() {
　　　　int n1, n2;
　　　　printf("Please enter two positive integers: ");
　　　　scanf("%d %d", &n1, &n2);
　　　　printf("%d and %d's G.C.D is %d.", n1, n2, hcf(n1, n2));
　　　　return 0;
}
int hcf(int n1, int n2) {
　　　　if (n2　!= 0)
　　　　　　　　return hcf(n2, n1　% n2);
　　　　else
　　　　　　　　return n1;
}

Output Result

Enter two positive integers:　366
60
366and6The G.C.D of 0 is6.

In this program, recursive calls are made until the value n2equals 0.

Comprehensive Collection of C Programming Examples