Question

实际上我想以简单的结构实现堆栈。

为什么下面的代码显示垃圾而不是项目？堆栈完全推送下一个项目后它会变为无穷大？还有其他方法可以使用数组实现堆栈。但我想试试这个。

我们如何在不使用指针的情况下实现堆栈？

#include <iostream>
#define size  5

using namespace std;

int main()
{
    int s[size];
    int top = -1,item,choice;
    char ans;

    do {
        cout << " =======================";
        cout << " \n|Implementation of Stack|\n";
        cout << " =======================";
        cout<<"\n MAIN NENUE";
        cout<<"\n 1. Push \n 2. Pop \n 3.Display ";
        cin>>choice;
        switch (choice) {
        case 1:
            cout<<"\n Enter the Item to be Pushed ";
            cin>>item;
            if (top != size -1) {
                top++;
                top = item;
            } else {
                cout<<"\nStack is Full ";
            }

        break;
        case 2:
            if (top == -1) {
                cout<<"\n Stack is Empty ";
            } else {
                int item;
                item = s[top];
                top--;
            }
            break;
        case 3:
            if (top == -1) {
                cout<<"\n Stack is Empty ";
            } else {
                for (int i = top; i >= 0; i--) {
                    cout<<"|" << s[i] << "|"<<endl;
                }
            }

            break;

        default:
            cout<<" \n You have Pressed Invalid Key";
            break;
        }

        cout<<"\n Do You Want To Continue ";
        cin>>ans;
    } while (ans == 'Y' || ans=='y');

    return item;
}

Answer 1

而不是这些陈述

       if (top != size -1) {
            top++;
            top = item;

写

       if (top != size -1) {
            s[++top] = item;

您可以为堆栈添加一些有用的功能。例如

int s[size];
int top = -1,item,choice;
char ans;

auto is_empty = [&top] { return top == -1; };
// ...

然后你可以写

    case 3:
        if ( is_empty() ) {
            cout<<"\n Stack is Empty ";
        } else {
            for (int i = top; i >= 0; i--) {
                cout<<"|" << s[i] << "|"<<endl;
            }
        }

        break;

Answer 2

我认为问题出在您的第一个if声明中。您应该将item分配给s[top]，但不能分配给top（因为您必须将item存储在数组s[]中）：

if (top != size -1) {
    top++;
    s[top] = item;
}

Answer 3

实际上，你从未将元素推入stack。

将您的push代码更改为此。

if (top < (size -1)) {
            ++top;
            s[top] = item;
        }

简单的堆栈实现

3 个答案: