/*
順序棧的實現：
初始化
入棧
出棧
計算棧的有效數據長度
獲取棧頂數據
清空棧
銷毀棧
*/

#include <stdio.h>
#include <stdlib.h>

#define ElemType int

typedef struct __stackInfo
{
ElemType *data;
unsigned int top;
unsigned int capacity;
} stackInfo;
/* 初始化 */
int initStack(stackInfo **ppS, unsigned int size)
{
if (NULL == ppS)
{
printf("ppNewStack point address is not exist\n");
return -1;
}

stackInfo *pNewStack = (stackInfo *)malloc(sizeof(stackInfo));
if (NULL == pNewStack)
{
printf("ppNewStack malloc fail\n");
return -1;
}

pNewStack->data = (ElemType *)malloc(sizeof(ElemType)*size);
if (NULL == pNewStack->data)
{
printf("ppNewStack databuf malloc fail\n");

/* 前面幾篇代碼就少了這裏，務必要小心，記個坑： 一旦直接推出，則泄漏內存pNewStack */
free(pNewStack);
return -1;
}

pNewStack->capacity = size;
pNewStack->top = 0;

*ppS = pNewStack;

return 0;
}
/* 入棧 */
int pushStack(stackInfo *pS, int val)
{
if (NULL == pS)
{
printf("pStack point NULL\n");
return -1;
}

if (pS->capacity == pS->top)
{
printf("pStack full\n");
return -1;
}

pS->data[pS->top] = val;
pS->top++;

return 0;
}
/* 出棧 */
int popStack(stackInfo *pS, int *val)
{
if ((NULL == pS) || (NULL == val))
{
printf("pStack point NULL or val point NULL\n");
return -1;
}

if (pS->top <= 0)
{
printf("pStack empty\n");
return -1;
}

pS->top--;
*val = pS->data[pS->top];

return 0;
}
/* 獲取棧頂數據 */
int topStack(stackInfo *pS, int *val)
{
if ((NULL == pS) || (NULL == val))
{
printf("pStack point NULL or val point NULL\n");
return -1;
}

if (0 >= pS->top)
{
printf("pStack empty\n");
return -1;
}

*val = pS->data[pS->top - 1];

return 0;
}
/* 計算棧中有效數據長度 */
int lengthOfStack(stackInfo *pS, unsigned int *val)
{
if ((NULL == pS) || (NULL == val))
{
printf("pStack point NULL or val point NULL\n");
return -1;
}

*val = pS->top;

return 0;
}
/* 清空棧 */
int emptyStack(stackInfo *pS)
{
if (NULL == pS)
{
printf("pStack point NULL\n");
return -1;
}

while(pS->top)
{
/* 小技巧：如果賦值為0即0，如果賦值為FF，因16、32位平臺的區別，鑒於可移植性考慮，賦值為0按位取反 */
pS->data[pS->top--] = ~0;
}

return 0;
}
/* 銷毀棧 */
int destoryStack(stackInfo **ppS)
{
if (NULL == ppS)
{
printf("pStack point address is not exist\n");
return -1;
}

if (NULL == *ppS)
{
printf("pStack point NULL\n");
return -1;
}

emptyStack(*ppS);
/* 關註點：1、兩塊動態內存需釋放 2、註意釋放的先後順序 */
free((*ppS)->data);
free(*ppS);

return 0;
}

/* 測試入口 */
int main(void)
{
stackInfo *pNewStack = NULL;
unsigned int length = 0;
int val = 0;

initStack(&pNewStack, 10);

lengthOfStack(pNewStack, &length);
printf("pNewStack valid length: %d\n", length);

/* 創建10個元素的棧，入棧11次，檢查軟件的容錯機制 */
for (int i=0; i<11; i++)
{
pushStack(pNewStack, i);
lengthOfStack(pNewStack, &length);
printf("pNewStack valid length: %d\n", length);
}
/* 入棧10個數據，出棧11次，檢查軟件的容錯機制 */
for (int i=0; i<11; i++)
{
topStack(pNewStack, &val);
printf("pNewStack top data: %d\n", val);
popStack(pNewStack, &val);
printf("popStack data: %d\n", val);
}

emptyStack(pNewStack);
lengthOfStack(pNewStack, &length);
printf("pNewStack valid length: %d\n", length);

destoryStack(&pNewStack);

return 0;
}

順序棧：創建&初始化、入棧、出棧、計算棧中有效數據長度、獲取棧頂數據、清空棧、銷毀棧