一个char转wchar

 class a2w {  wchar_t* buffer;public:  explicit a2w(const char* str):buffer(0)  {     if(str)    {      size_t nu = strlen(str);      size_t n = ::MultiByteToWideChar(CP_ACP,0,(const char *)str,int(nu),NULL,0);      buffer = new wchar_t[n+1];      ::MultiByteToWideChar(CP_ACP,0,(const char *)str,int(nu),buffer,int(n));    }  }  ~a2w() {  delete[] buffer;  }

  operator const wchar_t*() { return buffer; }

};