LeetCode Implement strStr() 实现strstr()

 1 int strStr(char* haystack, char* needle) {
 2         if (!haystack || !needle) return -1;
 3         for (int i = 0; ; ++i) {
 4             for (int j = 0; ; ++j) {
 5                 if (needle[j] == 0) return i;
 6                 if (haystack[i + j] == 0) return -1;
 7                 if (haystack[i + j] != needle[j]) break;
 8             }
 9         }
10 }