using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
 
namespace WindowsApplication2
{
	class Calculator
	{
		private Stack stack = new Stack();
 
		public void Push( double a )
		{
			stack.Push( a );
		}
		
		public double Pop()
		{
			return (double)stack.Pop();
		}
 
		/// Todo: make this a property called "Value" or "Result"...
		public double Peek()
		{
			return (double)stack.Peek();
		}
 
		public double Add()
		{
			Push( Pop() + Pop() );			
			return Peek();
		}
		
		public double Sub()
		{
			// The one at the top is subtracted from the next one down.
			// (Pop() - Pop()) would get the wrong result.
			Push( - Pop() + Pop() );  
			return Peek();
		}
		
		public double Mult()
		{
			Push( Pop() * Pop() );			
			return Peek();
		}
		
		public double Div()
		{
			double divisor = Pop();
			Push( Pop() / divisor );			
			return Peek();
		}
 
		public double Mod()
		{
			// Not relevant for floating point, so convert to int:
			int divisor = (int)Pop();
		
			Push( (int)Pop() % divisor );
			return Peek();
		}
 
		bool IsNum( string s )
		{
			// try converting it...
			try
			{
				float.Parse(s);
				return true;
			}
			catch( Exception e )
			{
				return false;
			}
		}
 
		public double Calc( string s )
		{
			String []parts = s.Split();
			char op = ' ';
									
			foreach( string part in parts )
			{
				if( IsNum(part) )
					Push( double.Parse( part ) );
				else
					op = part[0];
			}
 
			switch( op )
			{
				case '+': return Add();
				case '-': return Sub();
				case '*': return Mult();
				case '/': return Div();
				case '%': return Mod();
				default: return Peek();
			}
		}
 
	}
 
	public class Form1 : System.Windows.Forms.Form
	{
		private Calculator calculator = new Calculator();
 
		private System.Windows.Forms.Label label1;
		private System.Windows.Forms.Button button1;
		private System.Windows.Forms.TextBox textBox1;
		/// Required designer variable.
		private System.ComponentModel.Container components = null;
 
		public Form1()
		{
			//
			// Required for Windows Form Designer support
			//
			InitializeComponent();
 
			//
			// TODO: Add any constructor code after InitializeComponent call
			//
		}
 
		/// Clean up any resources being used.
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}
 
		#region Windows Form Designer generated code
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		private void InitializeComponent()
		{
			this.label1 = new System.Windows.Forms.Label();
			this.button1 = new System.Windows.Forms.Button();
			this.textBox1 = new System.Windows.Forms.TextBox();
			this.SuspendLayout();
			// 
			// label1
			// 
			this.label1.Location = new System.Drawing.Point(8, 8);
			this.label1.Name = "label1";
			this.label1.Size = new System.Drawing.Size(152, 23);
			this.label1.TabIndex = 0;
			this.label1.Text = "Enter Your Calculation";
			// 
			// button1
			// 
			this.button1.Location = new System.Drawing.Point(8, 56);
			this.button1.Name = "button1";
			this.button1.TabIndex = 1;
			this.button1.Text = "Enter";
			this.button1.Click += new System.EventHandler(this.button1_Click);
			// 
			// textBox1
			// 
			this.textBox1.Location = new System.Drawing.Point(8, 32);
			this.textBox1.Name = "textBox1";
			this.textBox1.TabIndex = 2;
			this.textBox1.Text = "1 + 1";
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(184, 86);
			this.Controls.AddRange(new System.Windows.Forms.Control[] {
																		  this.textBox1,
																		  this.button1,
																		  this.label1});
			this.Name = "Form1";
			this.Text = "Calculator";
			this.ResumeLayout(false);
 
		}
		#endregion
 
		/// The main entry point for the application.
		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}
 
		private void button1_Click(object sender, System.EventArgs e)
		{
			textBox1.Text = calculator.Calc( textBox1.Text ).ToString();
		}
	}
}