fname1.cpp

ThinkingC++中文版

//: C14:FName1.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 2000
// Copyright notice in Copyright.txt
// An fstream with a file name
#include "../require.h"
#include <iostream>
#include <fstream>


class FName1 {
private:
	ifstream file;
    string fileName;
    bool named;
public:
	FName1() : named(false) 
	{
	}
    FName1(const string& fname) : fileName(fname), file(fname.c_str()) 
	{
		assure(file, fileName);
		named = true;
	}
    string name() const 
	{ 
		return fileName; 
	}
    void name(const string& newName) 
	{
		if(named) 
			return; // Don't overwrite
		fileName = newName;
		named = true;
	}
    operator ifstream&() 
	{ 
		return file; 
	}
};

void main() 
{
    FName1 file("FName1.cpp");
    cout << file.name() << endl;
	
    // Error: close() not a member:
    //!  file.close();
} ///:~