【004】定位子串

int StrLoc(char *str, char *sub){
    int i = 0, j = 0, k = i;
    while (*(str+i) != '\0' && strlen(str+i) >= strlen(sub)){
        while (*(sub+j) == *(str+k)){
            k++;
            j++;
        }
        if(j-1 == strlen(sub)){
            return i;
        }else{
            i++;
            k = i;
            j = 0;
        }
    }
    return -1;
}