链式栈基本功能的简单实现

#include <iostream>
#include <stdlib.h>
using namespace std;


typedef struct list
{
        int data;
        struct list *next;
}node;

typedef struct listStack
{
        node *top;
        node *bottom;
}stack;

stack *createStack()
{
        node *p;
        stack *s = (stack *)malloc(sizeof(stack));
        s->top = NULL;
        s->bottom = NULL;
        int x;
        while(1)
        {
                cout<<"input element of stack(0 to exit):"<<endl;
                cin>>x;
                if(x != 0)
                {
                        if(s->top == NULL)
                        {
                                s->top = (node *)malloc(sizeof(node));
                                s->top->data = x;
                                s->bottom = s->top;
                        }
                        else
                        {
                                p = (node *)malloc(sizeof(node));
                                p->data = x;
                                p->next = s->top;
                                s->top = p;
                        }
                }
                else
                {
                        cout<<"create stack finished!"<<endl;
                        break;
                }
        }
        return s;
}

stack *push(stack *s, int x)
{
        node *p = (node *)malloc(sizeof(node));
        p->data = x;
        p->next = s->top;
        s->top = p;
        return s;
}

void display(stack *s)
{
        node *p = s->top;
        if(p == NULL)
        {
                cout<<"Empty Stack!"<<endl;
                return ;
        }
        cout<<"stack elements:"<<endl;
        while(p != s->bottom)
        {
                cout<<p->data<<endl;
                p = p->next;
        }
        cout<<p->data<<endl;
        return ;
}

stack *pop(stack *s, int &x)
{
        if(s->top == NULL)
        {
                cout<<"Empty Stack!"<<endl;
                return s;
        }
        else if(s->top == s->bottom)
        {
                node *p = s->top;
                x = p->data;
                s->top = NULL;
                s->bottom = NULL;
                free(p);
                return s;
        }
        else
        {
                node *p = s->top;
                x = p->data;
                s->top = p->next;
                free(p);
                return s;
        }
}

int length(stack *s)
{
        int count = 0;
        node *p;
        p = s->top;
        while(1)
        {
                if(p == s->bottom)
                        break;
                else
                {
                        count++;
                        p = p->next;
                }
        }
        if(p != NULL)
        {
                count++;
        }
        return count;
}
int main()
{
        int x;
        stack *s = createStack();
        display(s);
        cout<<"length of stack:"<<length(s)<<endl;
        cout<<"element to push:"<<endl;
        cin>>x;
        s = push(s, x);
        cout<<"After push:"<<endl;
        display(s);
        cout<<"length of stack:"<<length(s)<<endl;
        cout<<"After pop:"<<endl;
        s = pop(s, x);
        display(s);
        cout<<"length of stack:"<<length(s)<<endl;
        cout<<"pop element:"<<x<<endl;
        free(s);
        return 0;
}