fname1.cpp

来自「Think in C++文中代码实现」· C++ 代码 · 共 68 行

// File from page 515 in "Thinking in C++" by Bruce Eckel
//////////////////////////////////////////////////
// From the compressed package ECKELT02.ZIP 4/11/95
// (Original ECKELT01.ZIP dated 2/21/95)
// Copyright (c) Bruce Eckel, 1995 
// Source code file from the book "Thinking in C++", 
// Prentice Hall, 1995, ISBN: 0-13-917709-4
// All rights reserved EXCEPT as allowed by the following 
// statements: You may freely use this file for your own 
// work, including modifications and distribution in 
// executable form only. You may copy and distribute this 
// file, as long as it is only distributed in the complete 
// (compressed) package with the other files from this 
// book and you do not remove this copyright and notice. 
// You may not distribute modified versions of the source 
// code in this package. This package may be freely placed 
// on bulletin boards, internet nodes, shareware disks and 
// product vendor disks. You may not use this file in 
// printed media without the express permission of the 
// author. Bruce Eckel makes no 
// representation about the suitability of this software 
// for any purpose. It is provided "as is" without express 
// or implied warranty of any kind. The entire risk as to 
// the quality and performance of the software is with 
// you. Should the software prove defective, you assume 
// the cost of all necessary servicing, repair, or 
// correction. 
// If you think you've found an error, please 
// email all modified files with loudly commented changes 
// to: [e-mail] (please use the same 
// address for non-code errors found in the book).
//////////////////////////////////////////////////

//: FNAME1.CPP -- An fstream with a file name
#include <fstream.h>
#include <strstrea.h>
#include "..\allege.h"

class fname1 {
  ifstream File;
  enum { bsize = 100 };
  char buf[bsize];
  ostrstream Name;
  int nameset;
public:
  fname1() : Name(buf, bsize), nameset(0) {}
  fname1(const char* filename)
    : File(filename), Name(buf, bsize) {
      allegefile(File);
      Name << filename << ends;
      nameset = 1;
  }
  const char* name() const { return buf; }
  void name(const char* newname) {
    if(nameset) return; // Don't overwrite
    Name << newname << ends;
    nameset = 1;
  }
  operator ifstream&() { return File; }
};

main() {
  fname1 file("fname1.cpp");
  cout << file.name() << endl;
  // Error: rdbuf() not a member:
//!  cout << file.rdbuf() << endl;
}