链式栈存储实现及操作

/*
栈的构造与操作

  初始化
  压栈
  出栈
  遍历
  清空
*/
# include <stdio.h>
# include <stdlib.h>
# include <malloc.h>

typedef struct Node
{
	int data;
	struct Node * pNext;
}* PNODE, NODE;

typedef struct STACK
{
	PNODE pTop;
	PNODE pBottom;
}* PSTACK, STACK;

//初始化
void init(PSTACK pS)
{
	pS->pTop = (PNODE)malloc(sizeof(NODE));
	
	if (!pS->pTop)
	{
		printf("内存分配失败！\n");

		exit(-1);
	}
	else
	{
		pS->pTop->pNext = NULL;
		pS->pBottom = pS->pTop;
	}


	return;
}

//压栈
void push(PSTACK pS, int val)
{
	PNODE pNew = (PNODE)malloc(sizeof(NODE));

	if (!pNew)
	{
		printf("内存分配失败！\n");

		exit(-1);
	}
	else
	{
		pNew->pNext = pS->pTop;
		pNew->data = val;
		pS->pTop = pNew;

		printf("压栈成功！\n");
	}

	return;
}

//遍历
void traverse(PSTACK pS)
{
	PNODE pTemp = pS->pTop;

	if (!pTemp->pNext)
	{
		printf("空栈，遍历失败！\n");

		return;
	}
	else
	{
		while (pTemp->pNext)
		{
			printf("%d\n", pTemp->data);
			pTemp = pTemp->pNext;
		}

		printf("遍历完毕！\n");
	}

	return;
}

//出栈
void pop(PSTACK pS)
{
	int val;

	if (!pS->pTop->pNext)
	{
		printf("空栈，出栈失败！\n");
	}
	else
	{
		val = pS->pTop->data;
		pS->pTop = pS->pTop->pNext;

		printf("出栈成功，出栈元素：%d\n", val);
	}

	return;
}

//清空
void clear(PSTACK pS)
{
	PNODE pTemp;

	if (!pS->pTop->pNext)
	{
		printf("栈空！\n");

		return;
	}
	else
	{
		while (pS->pTop->pNext)
		{
			pTemp = pS->pTop;
			pS->pTop = pS->pTop->pNext;

			free(pTemp);
		}

		printf("清空成功！\n");
	}

	return;
}

int main(void)
{
	STACK s;

	init(&s);
	push(&s, 1);
	push(&s, 2);
	push(&s, 3);
	push(&s, 4);
	push(&s, 5);
	push(&s, 6);
	traverse(&s);
	pop(&s);
	traverse(&s);
	clear(&s);
	traverse(&s);

	return 0;
}