链栈的基础操作

2018/3/4#include <iostream>
#include<stdlib.h>

using namespace std;

typedef struct node {
int data;
struct node *next;
}Node;

typedef struct stack {
Node *top;
int count;
}Link_Stack;

/**创建一个空栈*/
Link_Stack * Creat_stack()
{
Link_Stack *p;
p = new Link_Stack; /**这一步不要忘！需要给p创建空间*/
p->count = 0;
p->top = NULL;

return p;
}

/**入栈操作：push*/
Link_Stack * Push_stack(Link_Stack *p, int elem)
{
if (NULL == p)
return NULL;

Node *temp;
temp = new Node;
temp->data = elem;

temp->next = p->top; /**注意这里和队列的入队操作不同，next指向不同，为了方便出栈操作*/
p->top = temp;

p->count += 1;

return p;
}

/**出栈操作：pop*/
Link_Stack * Pop_stack(Link_Stack *p)
{
Node *temp;
temp = p->top;
if (NULL == p->top)
{
cout << "The stack is empty." << endl;
return p;
}
else {
p->top = p->top->next; /** temp = temp->next; 千万不能这么写，看看下一步是什么？*/
delete temp;

p->count -= 1;

return p;
}
}

/**栈的遍历：输出栈*/
int Show_stack(Link_Stack *p)
{
Node *temp;
temp = p->top;

if (NULL == p->top)
{
cout << "The stack is empty." << endl;
return 0;
}
while (NULL != temp)
{
cout << temp->data << ' ';
temp = temp->next;
}
cout << endl;

return 0;
}

int main()
{
int i = 5;
int elem;
Link_Stack *p;
p = Creat_stack();
while (i--)
{
cin >> elem;
Push_stack(p, elem);
}
cout << "空栈插入5个元素后:" << endl;
Show_stack(p);

cout << "删除3个元素后:" << endl;
for (i = 3; i--;)
{
Pop_stack(p);
}
Show_stack(p);
cout << "count:" << p->count << endl;

cout << "删除2个元素后:" << endl;
for (i = 2; i--;)
{
Pop_stack(p);
}
Show_stack(p);
cout << "count:" << p->count << endl;

Push_stack(p, 6);
cout << "插入元素6后:" << endl;
Show_stack(p);
cout << "count:" << p->count << endl;

system("pause");
}