删除函数后，为什么仍然可以从指针类中调用函数? [英] Why can I still call a function from a pointer class after I delete it?

问题描述

可能重复:
何时会发生什么我在NULL对象指针上调用成员函数吗?

Possible Duplicate:
What will happen when I call a member function on a NULL object pointer?

#include <iostream>
#include <string>

using namespace std;

class myClass{
private:
        int *x, *y, *z;

public:
        myClass();
    ~myClass();
    void display();
    void math(int,int,int);
};


void myClass::math(int x,int y,int z){
    this->x = new int;
    this->y = new int;
    this->z = new int;

    *this->x = x;
    *this->y = y;
    *this->z = z;

    cout << "result: " << (x*y)+z << endl;
}

myClass::~myClass(){
    delete x;
    delete y;
    delete z;
}

void myClass::display(){
    cout << x << y << z << endl;
}

myClass::myClass(){
    x=0;
    y=0;
    z=0;
}


int main()
{
    myClass myclass;
    myClass *myptr;
    myptr = new myClass();

        myclass.math(1,1,1);

myptr->math(1,1,1);

delete myptr;

myptr->math(1,1,1);  **//why does this still print?**



int t;
cin >> t;

 }

::: OUTPUT :::

:::OUTPUT:::

结果:2

结果:2

结果:2

我只是在用C ++弄乱，试图了解更多信息.我想看看删除操作符到底是做什么的.为什么删除对象后仍然得到"result:2"的第三个输出?

I am just messing around in C++ trying to learn more. I wanted to see what exactly the delete operator does. Why is it that I still get a third output of "result: 2" after deleting the object?

推荐答案

对象内存可能尚未被其他内容覆盖.不要做这种事情，这是未定义的行为

The object memory probably was not overwritten by something else yet. Do not do such things, it is undefined behavior

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