C++拷贝构造函数

#include <iostream>
using namespace std;

class Line
{
public:
	int getLength(void);
	Line(int len);
	Line(const Line &obj); // 拷贝构造函数
	~Line();

private:
	int *ptr;
};

Line::Line(int len)
{
	cout << "调用构造函数" << endl;

	// 为指针分配内存
	ptr = new int;
	*ptr = len;
}

Line::Line(const Line &obj)
{
	cout << "调用拷贝构造函数并为指针ptr分配内存" << endl;
	ptr = new int;
	*ptr = *obj.ptr; // 拷贝值
}

Line::~Line(void)
{
	cout << "释放内存" << endl;
	delete ptr;
}

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

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

int main()
{
	Line line(10);
	display(line);

	system("pause");

	return 0;
}