C链栈实现

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

const int TRUE = 1;
const int FALSE = 0;
const int null = 0;

void initStack(StackLink *s) {
	s->top = (StackNode *) malloc(sizeof(StackNode));
	s->size = 0;
	s->top->data = 0;
	s->top->next = null;
}

status pop(StackLink *s, ElemType *elem) {
	StackNode *p;
	if (s->top->next == null) {
		printf("the stack is empty\n");
		return FALSE;
	} else {
		*elem = s->top->next->data;
		p = s->top;
		s->top = s->top->next;
		s->size--;
		free(p);
		return TRUE;
	}
}

void push(StackLink *s, ElemType x) {
	StackNode *p;
	p = (StackNode *) malloc(sizeof(StackNode));
	p->data = x;
	p->next = s->top->next;
	s->top->next = p;
	s->size++;
}

void getTop(StackLink *s, ElemType *elem) {
	if (s == null)
		printf("the stack is empty!\n");
	*elem = s->top->next->data;
}

status isEmpty(StackLink *s) {
	if (s->size == 0) {
		return TRUE;
	} else {
		return FALSE;
	}
}

void traverse(StackLink *s) {
	StackNode *p;
	p = s->top->next;
	printf("traverse the StackNode:\n");
	if (isEmpty(s))
		printf("the StackNode is empty!\n");
	else {
		while (p) {
			printf("->%d", p->data);
			p = p->next;
		}
	}
}

void clear(StackLink *s) {
	StackNode *p, *q;
	p = s->top;
	while (p) {
		q = p; /* "q" is the prev node of node "p"*/
		p = p->next;
		free(q);
	}
	s->size = 0;
}

int getStackLength(StackLink *s) {
	return s->size;
}