复制构造函数和重载的赋值运算符 [英] Copy Constructor AND Overloaded Assignment Operator

问题描述

大家好..

希望你身体健康。好吧，我正在尝试更新运算符重载的概念，我在这里编写了一个简单的代码：

Hello guys..
Hope You Are At Good Sate Of Health. Well i'm trying to refresh the concept of operator overloading, I've written a simple code here:

#include <iostream>
using namespace std;

class Test
{
private:
	int a;
	int *b;
public:
    Test();
	Test(int x, int y);
	void print();
	Test(const Test& yourTest); // Copy Constructor -> const className(const className&)
	const Test& operator=(const Test& anotherTest); // Assignment Operator -> const className &operator=(const className&)
	~Test(); // Destructor
};
Test::Test()
{
    a = -69;
    b = new int;
}
Test::Test(int x, int y)
{
	cout << "Constructor Called .. " << endl;
	a = x;
	b = new int(y);
	//*b = y;
}
void Test::print()
{
	cout << "A = " << a  << "\t" << "B = " << b << "\n\n";
}
Test::Test(const Test& yourTest)
{
	cout << "Copy Constructor Called .. " << endl;
	a = yourTest.a;
	b = new int;
	*b = *(yourTest.b);
}
const Test& Test::operator=(const Test& anotherTest)
{
	cout << "Assignment Operator Called .. " << endl;
	if (this != &anotherTest){
		a = anotherTest.a;
		delete b;
		*b = *(anotherTest.b);
		return *this;
	}
	else
	cout << "Self Assignment .. " << endl;

}
Test::~Test(){
	delete b;
}
int main()
{
	Test T1(2,3)
	Test T2(T1);
	T1.print();
	T2.print();
	return 0;
}

问题是，int * b的值是垃圾，请你帮我识别错误.. ??！



我敏锐地等你回复..

The issue is, the value of int *b is garbage, could you please help me to identify the mistake .. ??!

I keenly waiting You Reply ..

推荐答案

你应该打印 * b 而不是 b ，在 Test :: print 功能。

另一个问题：您应该从中删除​​删除b; 行运算符= 。您不必删除内存，只需为其分配一个新值。

Another issue: You should remove the delete b; line from operator=. You don't have to delete the memory, just assign a new value to it.

#include <conio.h>
#include <iostream>
using namespace std;
 
class Test
{
private:
	int a;
	int *b;
public:
    Test();
	Test(int x, int y);
	void print();
	Test(const Test& yourTest); // Copy Constructor -> const className(const className&)
	const Test& operator=(const Test& anotherTest); // Assignment Operator -> const className &operator=(const className&)
	~Test(); // Destructor
};

Test::Test()
{
    a = -69;
    b = new int;
	*b=0;
}

Test::Test(int x, int y)
{
	cout << "Constructor Called .. " << endl;
	a = x;
	b = new int;
	*b = y;
}

void Test::print()
{
	cout << "A = " << a  << "\t" << "B = " << *b << "\n\n";
}

Test::Test(const Test& yourTest)
{
	cout << "Copy Constructor Called .. " << endl;
	a = yourTest.a;
	b = new int;
	*b = *(yourTest.b);
}
const Test& Test::operator=(const Test& anotherTest)
{
	cout << "Assignment Operator Called .. " << endl;
	if (this != &anotherTest){
		a = anotherTest.a;
		//delete b;
		*b = *(anotherTest.b);
		return *this;
	}
	else
         {
	cout << "Self Assignment .. " << endl;
         return *this; 
         }
 
}

Test::~Test(){
	delete b;
}

int main()
{
	Test T1(2,3);
	Test T2(T1);
	T1.print();
	T2.print();

	getch();
	return 0;
}

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