iosop.cpp

来自「Think in C++文中代码实现」· C++ 代码 · 共 84 行

// File from page 428 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).
//////////////////////////////////////////////////

//: IOSOP.CPP -- Iostream operator overloading
// Example of non-member overloaded operators
#include <iostream.h>
#include <strstrea.h>
#include <string.h>
#include "..\allege.h"

class intarray {
  enum { sz = 5 };
  int i[sz];
public:
  intarray() {
    memset(i, 0, sz* sizeof(*i));
  }
  int& operator[](int x) {
    allege(x >= 0 && x < sz, 
           "operator[] out of range");
    return i[x];
  }
  friend ostream&
    operator<<(ostream& os,
               const intarray& ia);
  friend istream&
    operator>>(istream& is, intarray& ia);
};

ostream& operator<<(ostream& os,
                    const intarray& ia){
  for(int j = 0; j < ia.sz; j++) {
    os << ia.i[j];
    if(j != ia.sz -1)
      os << ", ";
  }
  os << endl;
  return os;
}

istream& operator>>(istream& is, intarray& ia){
  for(int j = 0; j < ia.sz; j++)
    is >> ia.i[j];
  return is;
}

main() {
  istrstream input("47 34 56 92 103");
  intarray I;
  input >> I;
  I[4] = -1; // Use overloaded operator[]
  cout << I;
}