string与wstring转换

方法一：MultiByteToWideChar、WideCharToMultiByte

 1 BOOL StringToWString(const std::string &str,std::wstring &wstr)
 2 {    
 3     int nLen = (int)str.length();    
 4     wstr.resize(nLen,L' ');
 5 
 6     int nResult = MultiByteToWideChar(CP_ACP,0,(LPCSTR)str.c_str(),nLen,(LPWSTR)wstr.c_str(),nLen);
 7 
 8     if (nResult == 0)
 9     {
10         return FALSE;
11     }
12 
13     return TRUE;
14 }
15 //wstring高字节不为0，返回FALSE
16 BOOL WStringToString(const std::wstring &wstr,std::string &str)
17 {    
18     int nLen = (int)wstr.length();    
19     str.resize(nLen,' ');
20 
21     int nResult = WideCharToMultiByte(CP_ACP,0,(LPCWSTR)wstr.c_str(),nLen,(LPSTR)str.c_str(),nLen,NULL,NULL);
22 
23     if (nResult == 0)
24     {
25         return FALSE;
26     }
27 
28     return TRUE;
29 }

方法二：std::copy

 1 std::wstring StringToWString(const std::string &str)
 2 {
 3     std::wstring wstr(str.length(),L' ');
 4     std::copy(str.begin(), str.end(), wstr.begin());
 5     return wstr; 
 6 }
 7 
 8 //只拷贝低字节至string中
 9 std::string WStringToString(const std::wstring &wstr)
10 {
11     std::string str(wstr.length(), ' ');
12     std::copy(wstr.begin(), wstr.end(), str.begin());
13     return str; 
14 }