剛從C#開始轉C++，有很多東西不理解，如下邊這段程式碼：

  #include <fstream>
  #include <iostream>
  
  int main() {
     using namespace std;
     ifstream file;
     basic_ifstream <wchar_t> wfile;
     char c;
     // Open and close with a basic_filebuf
     file.rdbuf()->open( "basic_filebuf_close.txt", ios::in );
     file >> c;
     cout << c << endl;
     file.rdbuf( )->close( );
  
     // Open/close directly
     file.open( "iotest.txt" );
     file >> c;
     cout << c << endl;
     file.close( );
  
     // open a file with a wide character name
     wfile.open( L"iotest.txt" );
  
     // Open and close a nonexistent with a basic_filebuf
     file.rdbuf()->open( "ziotest.txt", ios::in );
     cout << file.fail() << endl;
     file.rdbuf( )->close( );
  
     // Open/close directly
     file.open( "ziotest.txt" );
     cout << file.fail() << endl;
     file.close( );
  }

下邊是我跟大牛的聊天記錄，疑問解開。（有個大牛幫解答疑問感覺就是爽啊！）