MSDN 对于lstrcmp()返回值的解释：
If the string pointed to by lpString1 is less than the string pointed to by lpString2, the return value is negative.
If the string pointed to by lpString1 is greater than the string pointed to by lpString2, the return value is positive.
[COLOR="DarkRed"]If the strings are equal, the return value is zero.[/COLOR]
