//原理：利用两个栈，一个记录最小值，一个记录数据。

 using System;

 using System.Collections.Generic;

 using System.Linq;

 using System.Threading.Tasks;

 namespace StackGetMinValues

 {

     public class Program

     {

         public void Main(string[] args)

         {

             MyStack myStack = new MyStack();

             myStack.Push();

             myStack.Push();

             myStack.Push();

             myStack.Push();

             myStack.Push(-);

             myStack.Push();

             Console.WriteLine(myStack.GetMinValue());

             myStack.Pop();

             Console.WriteLine(myStack.GetMinValue());

             myStack.Pop();

             Console.WriteLine(myStack.GetMinValue());

             Console.ReadLine();

         }

     }

     public class MyStack

     {

         public Stack<int> stackData;

         public Stack<int> stackMin;

         public MyStack()

         {

             stackData = new Stack<int>();

             stackMin = new Stack<int>();

         }

         public void Push(int number)

         {

             if (number.GetType() != typeof(int)) throw new ArgumentException("必须输入数字");

             if (stackData.Count() == )

             {

                 stackData.Push(number);

                 stackMin.Push(number);

                 return;

             }

             stackData.Push(number);

             if (stackMin.Peek() > number)

             {

                 stackMin.Push(number);

             }

         }

         public int Pop()

         {

             if (stackData.Count() == ) throw new IndexOutOfRangeException("栈对象为空");

             var value = stackData.Pop();

             if (value == stackMin.Peek())

             {

                 stackMin.Pop();

             }

             return value;

         }

         public int GetMinValue()

         {

             if (stackMin.Count() == ) throw new IndexOutOfRangeException("最小值栈对象为空");

             return stackMin.Peek();

         }

     }

 }