slice.cpp

来自「Think in C++文中代码实现」· C++ 代码 · 共 62 行

// File from page 560 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).
//////////////////////////////////////////////////

//: SLICE.CPP -- Object slicing
#include <iostream.h>

class base {
  int i;
public:
  base(int I = 0) : i(I) {}
  virtual int sum() const { return i; }
};

class derived : public base {
  int j;
public:
  derived(int I = 0, int J = 0)
    : base(I), j(J) {}
  int sum() const { return base::sum() + j; }
};

void call(base b) {
  cout << "sum = " << b.sum() << endl;
}  
    
main() {
  base b(10);
  derived d(10, 47);
  call(b);
  call(d);
}