Determine the greatest common divisor of two integers using Euclid's algorithm

euclid.c

/****************************************************************************
 * euclid.c
 *
 * Determine the greatest common divisor of two integers using Euclid's algorithm
 * 
 * usage: ./eculid num1 num2
 ***************************************************************************/
 
 #include <stdio.h>
 #include <stdlib.h>
 
 int gcdRecursive(int a, int b);
 int gcdIterative(int a, int b);
 
 int main(int argc, char *argv[])
 {
     // Ensure proper usage
     if (argc != 3)
     {
         fprintf(stderr, "Usage: ./euclid num1 num2\n");
         return 1;
     }
     
     // Get integers to find the greatest common divisor
     int num1 = atoi(argv[1]);
     int num2 = atoi(argv[2]);
     
     // Call the recursive function to find the greatest common divisor
     int gcd = gcdRecursive(num1, num2);
     
     // Print results
     printf("Recursive function:\n");
     printf("The greatest common divisor of %i and %i is %i\n\n", num1, num2, gcd);
     
     printf("Iterative function:\n");
     printf("The greatest common divisor of %i and %i is %i\n", num1, num2, gcd);
     
     return 0;
 }
 
 // Find the greatest common divisor using recursion
 int gcdRecursive(int a, int b)
 {
     if (b == 0)
     {
         return a;
     }
     
     return gcdRecursive(b, a % b);
 }
 
 // Find the greatest common divisor using iteration
 int gcdIterative(int a, int b)
 {
     int t;
     
     while (b != 0)
     {
         t = b;
         b = a % b;
         a = t;
     }
     
     return a;  
}