#include "stdafx.h"
Status InitStack(stack* s)
{
 //構造一個空棧
 s->base = (SElemType*) malloc(STACK_INIT_SIZE*sizeof(SElemType));
 if(s->base==NULL) return ERROR;
 s->top = s->base ; //表示空棧
 s->stacksize = STACK_INIT_SIZE ;
 return OK;
}

Status DestroyStack(stack* s)
{
  //銷毀棧s，s不再存在
    free(s->base);
    s->top =s->base =NULL;
    free(s); 
    return 0;
}

Status ClearStack(stack* s)
{
  //把棧s清空
    s->top = s->base ;
    return OK;
}

int StackEmpty(stack* s)
{
 //若棧s為空，則返回true, 否則返回false
  if(s->top == s->base) return 1;
  return 0;
}
 
int StackLength(stack* s)
{
  //返回s的元素的個數，即棧的長度
    return s->top - s->base;
}

Status GetTop(stack* s,SElemType* e)
{
 // 若棧不空，則用e返回s的棧頂元素，操作成功返回0 ,失敗返回-1
    if(s->top==s->base) return ERROR;
    *e= *(s->top-1);
    return OK;
}

Status Push(stack* s,SElemType e)
{//插入元素e為新棧頂的元素
    if(s->top-s->base >= s->stacksize)
    { //棧滿，追加存儲空間
        s->base  = (SElemType* ) realloc(s->base,(s->stacksize+STACKINCRAMENT)*sizeof(SElemType));
        if(s->base==NULL) return ERROR;
        s->top = s->base +s->stacksize;
        s->stacksize += STACKINCRAMENT;
    }
    *(s->top)++ = e;
    return OK;
}

Status Pop(stack* s,SElemType* e)
{ //若棧不空，則刪除s的棧頂元素，用e返回其值 
 //操作成功返回0 ，失敗返回-1
    if(s->top==s->base) return ERROR;
    *e = *(--s->top);
    return OK;
}


Status StackTraverse(stack* s)
{
 //從棧頂依次對棧中的每一個元素進行遍歷
    SElemType* temp = s->top;
    for(temp--;temp!=s->base-1;temp--)
    {
       printf("%d ",*temp);
    }
    printf("\n");
    return OK;
}