using System;
namespace Stack {
public class Stack
{ // 节点类
class Node
{ // 节点有两个属性：自己、指向下一个节点
public Node Next;
public object Value;
public Node(object value) : this(value, null) { }
public Node(object value, Node next)
{
Next = next;
Value = value;
}
}
// first: 栈最上面一个节点
private Node first = null;
// count: 栈中节点的数量
private int count = 0;
// 判空属性，提供get访问器
public bool Empty {
get {
return (first == null);
}
}
// 计数属性，提供get访问器
public int Count {
get {
return count;
}
}
// 压栈操作，注意返回object
public object Pop() {
if (first == null) {
throw new InvalidOperationException("Cant pop from an empty stack"); //无效操作异常
} else {
object temp = first.Value;
first = first.Next;
count--;
return temp;
}
}
// 弹栈操作，返回空
public void Push(object o) {
first = new Node(o, first);
count++;
}
}
class StackApp {
static void Main() {
Stack s = new Stack();
if (s.Empty)
Console.WriteLine("堆栈为空");
else
Console.WriteLine("堆栈非空");
// 往栈中压入5个节点
for (int i = 0; i < 5; i++)
s.Push(i);
Console.WriteLine("往堆栈中压入了{0}个元素", s.Count);
// 把栈中节点全部弹出来
for (int i = 0; i < 5; i++)
Console.WriteLine("弹出了第{0}个元素，还剩{1}个元素。", (int)s.Pop() + 1, s.Count);
s = null;
Console.ReadLine();
}
}
}
堆：先进先出
栈：先进后出