4-2.cpp

拷贝函数的实验源代码

#include <iostream.h>

class X
{
public:
	X(int);
	X(X &);
	~X();
	void set(int s){num=s;}
	int get()
	{int s;
	  s=num;
	  return s;
	}
private:
	int num;
};

X::X(int n)
{	num=n;
 	cout<<"构造一个对象..."<<endl;}

X::X(X &a)
{
	num=a.get();
    cout<<"拷贝构造一个对象..."<<endl;
}

X::~X()
{
	cout<<"析构一个对象..."<<endl;
}

X f(X);
void main()
{	X a(3);
 	cout<<"a的值是："<<a.get()<<endl;
 	X b=f(X(2));
 	cout<<"b的值是："<<b.get()<<endl;
 	a=f(a);
 	cout<<"a经函数F设置后为原值2倍的值为："<<a.get()<<endl;
}

X f(X z)
{  	int y;
   	X d(1);
   	y=z.get();
   	d.set(2*y);
   	return d;
}