hey i guys iam trying to make a postfix calculator it works very well with the number but when u tried to add parantheses the code doesnt seem to work well

/*Programmer : Ramy Selim
 * E-mail:themurder2005@hotmail.com
 * postfix calculator
 */

using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace postcalc
{
    public partial class Form1 : Form
    {
        //Defining two stack
        Stack stack = new Stack();
        Stack revstack = new Stack();

        /*my Variables*/
        float result;
        float first,second;
        string temp;
        string lastnum;
        char[] ramy;
        bool empty = true;
        /*end variables*/
        

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
          
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Rese();
            Start();
            checkingIfThereOtherOperator(); // checking if there any other operations
            reversestack(); // reverse the stack
            Display(); // displaynig the postfix


            //Reversing the stack again
            while (stack.Count != 0)
                revstack.Push(stack.Pop());


            calculate(); //calculate
            


        }



        /*Reseting all variable*/
        private void Rese()
        {
            stack.Clear();
            revstack.Clear();
            result = 0;
            first= second =0;
            temp = "";
            lastnum ="";
            empty = true;
        }



        //Displaying the postfix expression
        private void Display()
        {
            textBox2.Text = "";


            while (revstack.Count != 0)
            {
                temp = revstack.Pop().ToString();
                textBox2.Text = textBox2.Text + temp + " ";
                stack.Push(temp);
            }
        }


        //start the main
        private void Start()
        {

            ramy = textBox1.Text.ToCharArray();

            foreach (char c in ramy)
            {
                if (char.IsDigit(c))
                    lastnum = lastnum + c.ToString();
                else
                {
                
                        stack.Push(lastnum);
                        lastnum = "";
                

                    if (empty)
                    {
                        revstack.Push(c);
                        empty = false;
                    }
                    else
                        check(c);

                }

            }

            stack.Push(lastnum);
            lastnum = "";
        }


        //claculate the infix
        private void calculate()
        {
            try
            {
                while (revstack.Count != 0)
                {
                    lastnum = revstack.Pop().ToString();
                    SeeWhatCanUDo();
                }

                textBox3.Text = stack.Pop().ToString();
            }
            catch (Exception e)
            { MessageBox.Show("Sign error","Romz"); }
        }

        private void SeeWhatCanUDo()
        {
            try
            {
                lastnum.ToCharArray();
                // MessageBox.Show(lastnum[0].ToString());
                if (char.IsDigit(lastnum[0]))
                {
                    lastnum.ToString();
                    stack.Push(lastnum);
                    lastnum = "";
                }
                else
                {
                    lastnum.ToString();
                    result = claculate();
                    stack.Push(result);
                }
            }
            catch (Exception e)
            {
                //MessageBox.Show("Sign error", "Romz"); 
            }
       
            
        }


        //complete calculate the infix
        private float claculate()
        {
            second = float.Parse(stack.Pop().ToString());
            first = float.Parse(stack.Pop().ToString());

            switch (lastnum)
            {
                case "+":
                    result =  first + second;
                    break;
                case "-":
                    result =  first - second;
                    break;
                case "*":
                    result = first * second;
                    break;
                case "/":
                    result =  first / second;
                    break;
            }

            return result;  
        }

  
        private void reversestack()
        {
            while (stack.Count != 0)
                revstack.Push(stack.Pop());

           
           
        }



        private void checkingIfThereOtherOperator()
        {
            while (revstack.Count != 0)
                    stack.Push(revstack.Pop());
        }



        private void check(char c)
        {
            switch (c)
            {
                case '+':
                  
                        while (revstack.Count != 0)
                            stack.Push(revstack.Pop());

                        revstack.Push(c);
                    
                    break;
                case '-':
                    while (revstack.Count != 0)
                        stack.Push(revstack.Pop());

                    revstack.Push(c);
                    break;
                case '*':

                    while (revstack.Count != 0)
                        if (revstack.Peek().ToString() == "*" || revstack.Peek().ToString() == "/")
                            stack.Push(revstack.Pop());
                        else
                            break;

                     revstack.Push(c);
                    break;
                case '/':
                    while (revstack.Count != 0)
                        if (revstack.Peek().ToString() == "*" || revstack.Peek().ToString() == "/")
                            stack.Push(revstack.Pop());
                        else
                            break;
                

                    revstack.Push(c);
                    break;
                case '(':
                    revstack.Push(c);
                    break;
                case ')':
                    while (revstack.Count != 0)
                    {
                        if (revstack.Peek().ToString() == "*" || revstack.Peek().ToString() == "/" ||
                            revstack.Peek().ToString() == "+" || revstack.Peek().ToString() == "-")
                            stack.Push(revstack.Pop());
                        else
                            break;
                    }
                    revstack.Pop();
                    break;
            }
        }
    }
}

Take a simple expression like (1+1) and see what happens when you debug it.

yea i did , and the problems is that in the case ')' loop id doesnt go to the else condititon and pop the '(' !!!! i dont know how when the if condition only pops when it see +,-,*,/ ??

A break takes you out of the case. So when you execute the else, the statements after the while never get executed.