Basically you need a strstr function of C...
If string contains substring, the return value is the location of the first matching instance of substring in string. If string doesn't contain substring, the return value is 0. Matching is done on an exact character-for-character basis with no wildcards or special characters., if found then returns the starting position of the substring within the string.
Here is the sample implemetation -
char *
strstr(string, substring)
register char *string; /* String to search. */
char *substring; /* Substring to try to find in string. */
{
register char *a, *b;
/* First scan quickly through the two strings looking for a
* single-character match. When it's found, then compare the
* rest of the substring.
*/
b = substring;
if (*b == 0) {
return string;
}
for ( ; *string != 0; string += 1) {
if (*string != *b) {
continue;
}
a = string;
while (1) {
if (*b == 0) {
return string;
}
if (*a++ != *b++) {
break;
}
}
b = substring;
}
return (char *) 0;
}