c++——拷貝構造函數

#include<iostream>
using namespace std;

class Line 
{
public :
	int getLength(void);
	Line(int len);
	Line(const Line &obj);
	~Line();
	
private:
	int *ptr;
};

//成員函數定義
Line::Line(int len)
{
	cout << "調用構造函數" << endl;
	ptr = new int;//爲指針分配內存
	*ptr = len;
}

Line::Line(const Line &obj) 
{
	cout << "調用拷貝構造函數併爲指針ptr分配內存" << endl;
	ptr = new int;
	*ptr = *obj.ptr;//拷貝值
}

Line::~Line(void) 
{
	cout << "釋放內存" << endl;
	delete ptr;//釋放內存
}

int Line::getLength(void) {
	return *ptr;
}

void display(Line obj) 
{
	cout << "line大小：" << obj.getLength() << endl;
}

int main() 
{
	Line line1(10);

	Line line2 = line1;//調用拷貝構造函數

	display(line1);
	display(line2);

	return 0;
}