构造函数, 拷贝构造函数, 赋值操作重载各种情况实例演示

构造函数, 拷贝构造函数, 赋值操作重载各种情况实例演示:

#include <iostream>
#include <string>
using namespace std;

void trace(string str)
{
	cout << str <<endl;
}

class CTest
{
private:
	int m_i;
	string m_str;
public:
	CTest(int i = 0, string str = "C++ Test");	//重载构造函数
	CTest(CTest& test);	//拷贝构造函数
	~CTest(){}	//析构函数

	void showData();

	CTest& operator=(CTest& test);	//赋值函数操作符重载
};

CTest::CTest(int i, string str)
{
	m_i = i;
	m_str = str;
}

CTest::CTest(CTest& test)
{
	this->m_i = test.m_i;
	this->m_str = test.m_str;
	cout << "call copy construct function" <<endl;
}

void CTest::showData()
{
	cout << this->m_i <<endl;
	cout << this->m_str <<endl;
}

CTest& CTest::operator=(CTest& test)
{
	this->m_i = test.m_i;
	this->m_str = test.m_str;
	cout << "赋值操作符重载" <<endl;
	return *this;
}

int main(int argc, char *argv[])
{
	trace("创建CTest对象:test");
	CTest test(10);
	test.showData();
	//CTest test2 = test;	//调用到拷贝构造函数!!!, 因为有新对象创建


	trace("创建CTest对象:test2");
	CTest test2(20);
	test2.showData();

	trace("赋值test2=test");
	test2 = test;	//没有新对象创建, 调用的是操作符重载方法, 如果没重载=, 就是内存的简单拷贝
	test2.showData();
	return 0;
}