There are some standard method to translate among Cstring ,string and char[].

// Suppose
CString str;
std::string s;
char buf[SIZE];

// from CString to std::string
s = str;

// from std::string to CString
str = s.c_str();

// to char[]
_tcscpy(buf, str);
_tcscpy(buf, s.c_str());

// from char[]
str = buf;
s = buf;

Also, beware of unicode. If UNICODE is defined, you should convert between unicode and ansi versions. Better to use TCHAR instead of char and std::basic_string instead of std::string.