链栈的基本运算

链式栈的定义

#include <malloc.h>
typedef char ElemType;
typedef struct lsnode 
{    
    ElemType data;            /*存储结点数据*/
    struct lsnode *next;    /*指针域*/
} LinkStack;

初始化栈

void InitStack(LinkStack *&ls)        /*ls为引用型参数*/
{
    ls=NULL;
}

进栈运算

void Push(LinkStack *&ls,ElemType x)        /*进栈运算,ls为引用型参数*/
{
    LinkStack *p;
    p=(LinkStack *)malloc(sizeof(LinkStack));
    p->data=x;
    p->next=ls;
    ls=p;
}

出栈运算

int Pop(LinkStack *&ls,ElemType &x)        /*出栈运算,ls为引用型参数*/
{
    LinkStack *p;
    if (ls==NULL)     /*栈空,下溢出*/
        return 0;
    else 
    {
        p=ls;
        x=p->data;
        ls=p->next;
        free(p);
           return 1;
    }
}

取栈顶元素运算

int GetTop(LinkStack *ls,ElemType &x)    /*取栈顶元素运算*/
{
    if (ls==NULL)     /*栈空,下溢出*/
        return 0;
    else 
    {
        x=ls->data;
           return 1;
       }
}

判断栈空运算

int StackEmpty(LinkStack *ls)    /*判断栈空运算*/
{
    if (ls==NULL)
        return 1;
    else
        return 0;
}

main

void main()
{
    LinkStack *ls;
    ElemType e;
    InitStack(ls);
    printf("栈%s\n",(StackEmpty(ls)==1?"空":"不空"));
    printf("a进栈\n");Push(ls,'a');
    printf("b进栈\n");Push(ls,'b');
    printf("c进栈\n");Push(ls,'c');
    printf("d进栈\n");Push(ls,'d');
    printf("栈%s\n",(StackEmpty(ls)==1?"空":"不空"));
    GetTop(ls,e);
    printf("栈顶元素:%c\n",e);
    printf("出栈次序:");
    while (!StackEmpty(ls))
    {
        Pop(ls,e);
        printf("%c ",e);
    }
    printf("\n");
}