c++ - 如何使用方法覆盖在输出屏幕上显示堆栈整数值？

Question

最近我的实验室导师通过使用方法覆盖的概念(我们目前正在研究继承)在堆栈上给了我以下代码来运行:

//4.3. This example demonstrates that how we can use the concept of Overriding.
#include<iostream>
#include<conio.h>
using namespace std;

class myStack {
protected:  //NOTE: Can't be private because only my child class should have access to it
    enum {
        maximumnumberofboxes = 3 
    }; // enumerated is used before a user defined variable (maximumnumberofboxes) that contains a collection of built in datatypes. 
    //I have used it to tell the size of my stack array
    int stack[maximumnumberofboxes]; // my stack array of integers
    int topvalue;
    //Index to top of stack. An index accesses a specific element in my stack array (in this case, the top value)

public:
    Stack() //my stack constructor
    {
        topvalue = -1;  
    }

    void push(int valueinbox) //Define a function that pushes the value of a specific element in the stack space
    {
        stack[++topvalue] = valueinbox; //put the value on stack
    }

    int pop()  //Define a function that pulls off the value of a specific element in the stack space
    {
        return stack[topvalue--]; //take number off stack
    }

};


class childStack : public myStack //Single Inheritance
{
public:
    void push(int valueinbox)
    { //put the value on stack
        if(topvalue >= maximumnumberofboxes-1) //error if stack full
        {
            cout<<"topvalue = "<<valueinbox;
            cout<<"\ntopvalue= "<<topvalue;
            cout << "\nError: stack is full";
            exit(1);
        }
        cout<<"\ntopvalue= "<<topvalue;
        cout<<"\ntopindex= "<<valueinbox;

        myStack::push(valueinbox); //call push() function in myStack class using unary scope operator
    }

    int pop() //call pop() function to pull value off my stack
    {
        if(topvalue < 0) //shows error if my stack is empty
        { 
            cout << "\nError: stack is empty\n";
            exit(1);
        }
        return myStack::pop(); //call pop() in myStack class
    }

};

int main()
{
    childStack s1;
    s1.push(11); //push some values onto child stack
    s1.push(22);
    s1.push(33);

    cout << endl << s1.pop(); //pop some values from child stack
    cout << endl << s1.pop();
    cout << endl << s1.pop();
    cout << endl << s1.pop(); //oops, popped one too many...
    cout << endl;
    system("pause");
    getch();
    return 0;
}

我的输出屏幕显示如下:

topvalue=11
topvalue=4249067
Error: stack is full

我想知道如何在输出屏幕上显示主函数中提到的三个整数 (11,22,33) 而不会得到任何垃圾值？

Answer 1

我发现您的代码存在一些问题:

1. 我假设 Stack()意味着是类 myStack 的构造函数正确的？那么要实现它必须与您的类(class)同名( myStack() )。我不确定这段代码是如何在你的机器上编译的。
2. 你没有初始化你的数组int stack[maximumnumberofboxes] .所以一开始它可能会有一些垃圾值(value)。

注意:这一行cout << endl << s1.pop(); //oops, popped one too many...您的程序将退出，因此您将无法到达 system("pause");并查看控制台上实际打印的内容。