28. Implement strStr()

 1 int strStr(char* haystack, char* needle) {
 2     int len_hay;
 3     int len_need;
 4     int i,j;
 5     len_hay = strlen(haystack);
 6     len_need = strlen(needle);
 7     for(i = 0; i <= len_hay - len_need; i++)
 8     {
 9         for(j = 0; j < len_need; j++)
10             {
11                 if(needle[j] != haystack[i+j])
12                     break;
13             }
14         if(j == len_need)
15             return i;
16     }
17     return -1;
18     
19 }