怎样判断一个汉字的是什么编码

1、判断是否是GB2312
bool isGBCode(const string& strIn){unsigned char ch1;
unsigned char ch2;
if (strIn.size() >= 2){ch1 = (unsigned char)strIn.at(0);
ch2 = (unsigned char)strIn.at(1);
if (ch1>=176 && ch1=160 && ch2= 2){ch1 = (unsigned char)strIn.at(0);
ch2 = (unsigned char)strIn.at(1);
if (ch1>=129 && ch1=64 && ch2