//查詢指定字串在源字串中的位置
char* my_strstr(char *src,char *search)
{
    char *srctemp=src;
    char *searchtemp=search;
    while (*srctemp) {
        if (*srctemp++==*searchtemp) {
            if (*++searchtemp=='\0') {
                return srctemp-strlen(search);
            }
            continue;
        }
        else
        {
            searchtemp=search;
        }
    }
    return NULL;
}