数据结构学习之 堆栈

堆栈
顺序存储
#define maxsize 10;
typedef int elemtype;
struct stack{
	elemtype num[maxsize];
	int top;
};
1.判断堆栈是否为空
int emptyst(struct stack S)
{
	return(S.top == -1);
}
2.判断堆栈是否已满的函数
int fullst(struct stack S)
{
	if (S.top==maxsize)
		return (1);
	else 
		return(0);
}
3.元素入栈
void pushst(struct stack S,elemtype k)
{
	if (fullst(s))
		printf("overflow")
	;else
	{
		S.top++;
		S.num[S.top]=k;
	}
}
4.元素出栈
elemtype pop(struct stack S)
{
	elemtype temp;
	if(emptyst(S))
		printf("underflow");
	else
	{
		temp=S.num[S.top];
		S.top--;
		return (temp);
	}
}
链式存储
typedef int elemtype;
struct snode
{
	elemtype data;
	struct snode *next;
}s;
1.初始化链式栈
void initstl(struct snode *s)
{
	s->next=NULL;
}
2.链式栈的压入算法
void pushls(struct snode *s,elemtype k)
{
	struct snode *q;
	q= (struct snode *)malloc (sizeof (struct snode));
	q->data=k;
	q->next=s->next;
	s->next=q;
}
3.链式栈的元素弹出
elemtype popls(struct snode *s)
{
	elemtype x;
	struct snode *q;
	if(s->next==NULL)
	printf("underflow")
else {
	q=s->next;
	s->next=q->next;
	x=q->data;
	ferr(q);
	return(x);
}
}