assignment-s-19.c

Metadata

• Author — Amit Dutta
• Last updated — 22 Dec 2025
• License — MIT License (See the LICENSE file for details)

Problem Statement

Problem Statement

Write a program to calculate the GCD of two numbers (i) using recursion (ii) without recursion

Source Code

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#include <stdio.h>

int gcd_tail_rec(int, int);
int gcd_rec(int, int);
int gcd_ite(int, int);

int main()
{
    int a, b;
    printf("Enter two number: ");
    scanf("%d %d", &a, &b);
    if (a < 0)
        a = -a;
    if (b < 0)
        b = -b;
    printf("\nGCD (Tail-Recursion) of %d and %d is = %d", a, b, gcd_tail_rec(a, b));
    printf("\nGCD (Recursion) of %d and %d is      = %d", a, b, gcd_rec(a, b));
    printf("\nGCD (Iteration) of %d and %d is      = %d", a, b, gcd_ite(a, b));
    return 0;
}

int gcd_tail_rec(int a, int b)
{
    if (b == 0)
    {
        return a;
    }
    else
    {
        return gcd_tail_rec(b, a % b);
    }
}

int gcd_rec(int a, int b)
{
    if (b == 0)
    {
        return a;
    }
    else
    {
        return gcd_rec(b, a % b);
    }
}

int gcd_ite(int a, int b)
{
    int temp;
    while (b > 0)
    {
        temp = b;
        b = a % b;
        a = temp;
    }
    return a;
}