automaticoperatorequals.cpp

ThinkingC++中文版

//: C12:AutomaticOperatorEquals.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 2000
// Copyright notice in Copyright.txt
#include <iostream>
#include <string>
using namespace std;

class Cargo {
public:
  Cargo& operator=(const Cargo&) {
    cout << "inside Cargo::operator=()" << endl;
    return *this;
  }
};

class Truck {
private:
  Cargo b;
  char* p;
  int i;
/*
public:
	Truck& operator=(const Truck& t)
	{
		//释放当前对象有关的成员
		delete p;
		p = new char[...]
		strcpy(p,t.p);
		//当前对象有关的成员=t.相应成员
		i = t.i;
		b = t.b;
		return *this;
	}
*/
};

class parent{
public:
	parent& operator=(const parent& com)
	{
		cout<<"inside parent::operator=()"<<endl;
		return *this;
	}

};

class child:public parent{
};


class third{
	child c;
	char* p;
public:
	third& operator=(const third& t)
	{
		delete p;
		p = new char[::strlen(t.p)+1];
		::strcpy(p,t.p);
		c = t.c;  
		return *this;
	}
};

void main() {
  Truck a, b;
  a = b; // Prints: "inside Cargo::operator=()"
//  child m,n;
//  m=n;
} ///:~