C Program to find sum of two numbers using command line arguments

Program

#include<stdio.h>
void main(int argc, char * argv[]) {
   int i, sum = 0;
   if (argc != 3) {
      printf("You have forgot to type numbers.");
      exit(1);
   }
   printf("The sum is : ");
   for (i = 1; i < argc; i++)
      sum = sum + atoi(argv[i]);
   printf("%d", sum);
}

Output

./a.out 5 8
The sum is:	13