c++ widestring

/*
* convert to wide string 
*/

wchar_t *ConvertWideChar(char *cstr)
{
    int WLen = MultiByteToWideChar(CP_ACP, 0,cstr, -1,NULL,0);
    wchar_t * buffer = new wchar_t[WLen+1];
    int RetWLen = MultiByteToWideChar(CP_ACP, 0,cstr,  -1,buffer,WLen);
    buffer[WLen] = '\0';
    return buffer;
}

/*
* convert to mutibyte string 
*/
char *ConvertMutiString(wchar_t *buffer)
{
    int MLen =WideCharToMultiByte(CP_ACP, 0,buffer, -1,NULL, 0, NULL, NULL);  
    char* MultiBte = new char[MLen+1]; 
    int RetMLen = WideCharToMultiByte( CP_ACP, 0,buffer,-1,MultiBte,MLen,NULL,NULL); 
    MultiBte[MLen]='\0';
    return MultiBte;
}