链式栈基础

news2025/2/28 17:25:51

一.链式栈的栈顶在哪里?

二.链栈的结构:

typedef struct LSNode

{

int data;

struct LSNode* next;

}LSNode ,*PLStack;

//链栈的节点.由于栈顶在第一个数据节点,所以不需要top指针

三.链式栈的实现:

//初始化
void InitStack(PLStack ps)
{
   assert(ps != NULL);
   if (ps == NULL)
       return;
   ps->next = NULL;
}
//往栈中入数据(入栈操作)
bool Push(PLStack ps, int val)
{
   assert(ps != NULL);
   if (ps == NULL)
       return false;

   LSNode* p = (LSNode*)malloc(sizeof(LSNode));
   assert(p != NULL);

   p->data = val;
   p->next = ps->next;
   ps->next = p;

   return true;
}
//获取栈顶元素的值,但是不删除
bool GetTop(PLStack ps, int* rtval )
{
   assert(ps != NULL);
   if (ps == NULL)
       return false;

   if (IsEmpty(ps))
       return false;

       *rtval=ps->next->data;
       return true;
}
//获取栈顶元素的值,但是删除
bool Pop(PLStack ps, int* rtval)
{
   assert(ps != NULL);
   if (ps == NULL)
       return false;

   if (IsEmpty(ps))
       return false;

   LSNode* p = ps->next;
   *rtval = p->data;

   ps->next = p->next;
   free(p);
   return true;
}
//判空
bool IsEmpty(PLStack ps)
{
   return ps->next == NULL;
}
//获取栈中有效元素的个数
int GetLength(PLStack ps)
{
   assert(ps != NULL);
   if (ps == NULL)
       return -1;
   int count = 0;
   for (LSNode* p = ps->next; p != NULL; p = p->next)
   {
       count++;
   }
   return count;
}
//清空所有的数据
void Clear(PLStack ps)
{
   Destroy(ps);
}
//销毁
void Destroy(PLStack ps)
{
   //总是删除第一个数据节点
   LSNode* p;
   while (ps->next != NULL)
   {
       p = ps->next;
       ps->next = p->next;
       free(p);
   }
}