C :: Valid Email Address Check

Now I have to write a code which would determine whether an Email address is valid or not.

In my exercise a valid address should look like this : ___@___.___.il (___ for any letters)

E.g. Valid address:

something @ something . something . il Invalid: tami @ jce . ac . uk

(without spaces of course)

Code:
#include <iostream>
#include <string.h>
using namespace std;
int isValid (char s[]) {
int length=strlen(s), ind1=0, ind2=0;

[Code] ....

It doesn't work well. It says both addresses are wrong when the 1st one isn't.