In the following program i haven't used retur statement in "add" function but still the code runs perfect...
why??

#include <stdio.h>
#include <stdlib.h>

int add(int x , int y);
int main()
{   int a,b,c;
        printf("enter a number \n");
        scanf("%d" , &a);

    printf("enter a number \n");
        scanf("%d" , &b);
        printf("sum = %d \n" , add(a,b));

    return 0;
}

int add(int x , int y){

    int sum = x + y ;
}