建立栈数据类型和对它的相关操作

一. 建立栈数据类型

首先建立节点数据类型

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

再建立栈数据类型

typedef struct Stack
{
	PNODE pTop;   			// 该指针指向栈顶
	PNODE pBottom;			// 该指针指向栈底
}STACK, * PSTACK;

二. 栈的初始化

void init_stack(PSTACK pS)
{
	pS->pTop = (PNODE)malloc(sizeof(NODE));
	if(NULL == pS->pTop)
	{
		printf("动态内存分配失败！\n");
		exit(-1);
	}
	else
	{
		pS->pBottom = pS->pTop;
		pS->pTop->pNext = NULL;
	}

	return;
}

三. 压栈

void push_stack(PSTACK pS, int val)
{
	PNODE pNew = (PNODE)malloc(sizeof(NODE));
	pNew->data = val;
	pNew->pNext = pS->pTop;
	pS->pTop = pNew;

	return;
}

四. 遍历输出

void traverse_stack(PSTACK pS)
{
	PNODE p = pS->pTop;

	while(p != pS->pBottom)
	{
		printf("%d\t", p->data);
		p = p->pNext;
	}
	printf("\n");

	return;
}

五. 出栈

bool empty(PSTACK pS)
{
	if(pS->pTop == pS->pBottom)
		return true;
	else
		return false;
}

bool pop_stack(PSTACK pS, int * pVal)
{
	if(empty(pS))
	{
		return false;
	}
	else
	{	

		PNODE r = pS->pTop;
		*pVal = r->data;
		pS->pTop = r->pNext;
		free(r);
		r = NULL;

		return true;
	}
}

六. 清空

void clear(PSTACK pS)
{
	if(empty(pS))
	{
		return;
	}
	else
	{
		PNODE p = pS->pTop;
		PNODE q = NULL;

		while(p != pS->pBottom)
		{
			q = p->pNext;
			free(p);
			p = q;
		}
		pS->pTop = pS->pBottom;
	}
	
}