何时调用复制构造函数

1、按值传递对象

2、函数返回对象

3、复制初始化，即用一个对象初始化另一个对象

 

#include <iostream>
using namespace std;

class A
{
public:
	A()
	{
		cout << "constructor" << endl;
	}
	A(const A& a)
	{
		cout << "copy constructor" << endl;
	}
	~A()
	{
		cout << "destructor" << endl;
	}
	A* Clone()
	{
		return new A(*this);
	}
protected:
private:
};

void test1()	//复制初始化
{
	A a;
	A b = a;
}

void test2()	//复制初始化
{
	A a;
	A *b = new A(a);
	delete b;
}

void test3()	//复制初始化
{
	A *a = new A();
	A b = *a;
	delete a;
}

void test4()	//复制初始化
{
	A *a = new A();
	A *b = new A(*a);
	delete a;
	delete b;
}

void test5(A a)	//按值传递对象
{

}

void test6(const A& a)	//传递对象的引用
{

}

A test7()	//函数返回对象
{
	A a;
	return a;
}

int main()
{
	cout << "test1:" << endl;
	test1();
	cout << "test2:" << endl;
	test2();
	cout << "test3:" << endl;
	test3();
	cout << "test4:" << endl;
	test4();

	A a;
	cout << "test5:" << endl;
	test5(a);
	cout << "test6:" << endl;
	test6(a);
	cout << "test7:" << endl;
	test7();

	cout << "end test-------------------" << endl;

	return 0;
}

　　

输出结果为：