c++编码，请指教,希望有所改进，本人在网上看到的，很详细的，就是觉得还有缺陷-practice，need improve，wait for your help

qq xxtea 变种加密解密算法。另有 utc时间到系统本地时间的函数的实现。-qq xxtea variety of encryption and decryption algorithm. Another utc time to local time of the function of the system implementation.