defaultcopyconstructor.cpp

ThinkingC++中文版

//: C11:DefaultCopyConstructor.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 2000
// Copyright notice in Copyright.txt
// Automatic creation of the copy-constructor
#include <iostream>
#include <string>
using namespace std;

class WithCC { // With copy-constructor
public:
  // Explicit default constructor required:
  WithCC() 	{}
  WithCC(const WithCC&) {
    cout << "WithCC(WithCC&)" << endl;
  }
};

class WoCC { // Without copy-constructor
  string id;
public:
  WoCC(const string& ident = "") : id(ident) {}
  WoCC(const WoCC&)
  {
	  cout<<"WoCC(const WoCC&)"<<endl;
  }
  void print(const string& msg = "") const {
    if(msg.size() != 0) cout << msg << ": ";
    cout << id << endl;
  }
};

class Composite {
  WithCC withcc; // Embedded objects
  WoCC wocc;
public:
  Composite() : wocc("Composite()") {}
   void print(const string& msg = "") const {
    wocc.print(msg);
  }
  Composite(const Composite&)
  {
	  cout<< "Composite(const Composite&)" <<endl;
  } 
};

void main() {
  Composite c;
  c.print("Contents of c");
  cout << "Calling Composite copy-constructor" << endl;
  Composite c2 = c;  // Calls copy-constructor
  c2.print("Contents of c2");
} ///:~