char，string和CString转换

&1 string->char

string str0 = "sophia is a good girl.";

const char *str1 = str0.c_str();//string.c_str()返回的是const char类型

&2 char->string

char str2[100]="xinwen is also a good girl.";
string str3 = str2;

&3 string->CString

CString类是MFC中重新定义的字符串类，提供了更多的字符串操作处理功能。

CString cstr;
string str = "sophia is a good girl.";
cstr = str.c_str();

&4 CString->string

CString str0 = "sophia is wonderful!";
string str1 = str0.GetBuffer(0);