simpleassignment.cpp

ThinkingC++中文版

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

class Value {
  int a, b;
  float c;
public:
  Value(int aa = 0, int bb = 0, float cc = 0.0)	: a(aa), b(bb), c(cc) 
  {}
  Value& operator=(const Value& rv) 
  {
	  if ( &rv != this)
	  {
		  a = rv.a;
		  b = rv.b;
          c = rv.c;
	  }
	  return *this;	   
  }
  friend ostream& operator<<(ostream& os, const Value& rv) {
    return os << "a = " << rv.a << ", b = "
      << rv.b << ", c = " << rv.c;
  }
};

void main() 
{
  Value a, b(1, 2, 3.3);
  cout << "a: " << a << endl;
  cout << "b: " << b << endl;
  a = b;
  cout << "a after assignment: " << a << endl;
} ///:~