passingbigstructures3.cpp

ThinkingC++中文版

//: C11:PassingBigStructures.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 Big{
public:
    char buf[100];
    int i;
    long d;
	Big(){}//缺省构造函数
	//拷贝构造函数
	Big(Big& b)
	{
		cout << "I am in Big(Big& b)." << endl;
		i = b.i;
		d = b.d;
		::strcpy(buf,b.buf);
	}
	~Big()
	{
		cout << "I am in ~Big()." << endl;
	}
   
};

/*
Big bigfun(Big temp) {  //实参对象传递给形参对象时，调用拷贝初始化构造函数
  temp.i = 3; // Do something to the argument 
  temp.d = 3.3;
  ::strcpy(temp.buf,"I am temp!");
  return temp;//函数返回对象时，调用拷贝构造函数初始化一个匿名对象，在函数返回后该匿名对象作为函数返回值
}
*/

Big& bigfun(Big& temp) {  
  temp.i = 3; // Do something to the argument 
  temp.d = 3.3;
  ::strcpy(temp.buf,"I am temp!");
  return temp;
}



void main() 
{
	Big b1, b2;
	b1.i = 1;
	b1.d = 1.1;
	::strcpy(b1.buf,"I am b1!");
	b2.i = 2;
	b2.d = 2.2;
	::strcpy(b2.buf,"I am b2!");
	b2 = bigfun(b1);
}