（郝斌讲学）数据结构学习篇（四）---栈的CRUD操作

栈

栈类似于箱子。

静态栈、动态栈。

关于栈的操作

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

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

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

void init(PSTACK);
void push(PSTACK, int);
void traverse(PSTACK);
bool empty(PSTACK);
bool pop(PSTACK, int *);
void clear(PSTACK p);

int main(void)
{
	STACK s;
	int val;

	init(&s);
	push(&s, 1);
	push(&s, 2);
	push(&s, 3);
	push(&s, 4);
	push(&s, 5);
	push(&s, 6);
	push(&s, 7);
	traverse(&s);

	if(pop(&s, &val))
	{
		printf("出栈成功，出栈的元素是 %d \n", val);
	}
	else
	{
		printf("出栈失败\n");
	}
	traverse(&s);

	clear(&s);
	if(pop(&s, &val))
	{
		printf("出栈成功，出栈的元素是 %d \n", val);
	}
	else
	{
		printf("出栈失败\n");
	}

	return 0;
}

//完成一个栈的初始化
void init(PSTACK p)
{
	p->pTop = (PNODE)malloc(sizeof(NODE));
	if(NULL == p->pTop)
	{
		printf("动态内存分配失败\n");
		exit(-1);
	}
	else
	{
		p->pBottom = p->pTop;
		p->pTop->pNext = NULL;
	}

}

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

void traverse(PSTACK p)
{
	PNODE r = p->pTop;
	while(r != p->pBottom)
	{
		printf("%d ", r->data);
		r = r->pNext;
	}
	printf("\n");

	return;
}

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

//把p所指向的栈出栈一次，并把出栈的元素存入pval形参所指的变量中
bool pop(PSTACK p, int * pval)
{
	if(empty(p))
	{
		return false;
	}
	else
	{
		PNODE r = p->pTop;
		*pval = r->data;
		p->pTop = r->pNext;
		free(r);
		r = NULL;

		return true;
	}
}

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

		while(r != p->pBottom)
		{
			t = r->pNext;
			free(r);
			r = t;
		}
		p->pTop = p->pBottom;
	}
}

栈主要用于表达式求值，缓冲处理，迷宫，函数调用，中断...