malclass.cpp

来自「Think in C++文中代码实现」· C++ 代码 · 共 64 行

// File from page 462 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).
//////////////////////////////////////////////////

//: MALCLASS.CPP -- Malloc with class objects
// What you'd have to do if not for "new"
#include <stdlib.h> // Malloc() & free()
#include <string.h> // Memset() 
#include "..\allege.h"
#include <iostream.h>

class obj {
  int i, j, k;
  enum { sz = 100 };
  char buf[sz];
public:
  void initialize() { // Can't use constructor
    cout << "initializing obj" << endl;    
    i = j = k = 0;
    memset(buf, 0, sz);
  }
  void destroy() { // Can't use destructor
    cout << "destroying obj" << endl;
  }
};

main() {
  obj* Obj = (obj*)malloc(sizeof(obj));
  allegemem(Obj);
  Obj->initialize();
  // ... sometime later:
  Obj->destroy();
  free(Obj);
}