C# - 계산기 만들기2

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
 
namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        String oper="";
        double currentNumber = 0;
        double savedNumber = 0;
        public Form1()
        {
            InitializeComponent();
        }
        private void calcOper(ref String oper, ref double savedNumber, ref double currentNumber)
        {
           
                if (oper == "+") savedNumber += currentNumber;
                else if (oper == "-") savedNumber -= currentNumber;
                else if (oper == "*") savedNumber *= currentNumber;
                else if (oper == "/") savedNumber /= currentNumber;
                else savedNumber = currentNumber;
            
        }
        private void button1_Click(object sender, EventArgs e)
        {
            
            calcOper(ref oper, ref savedNumber, ref currentNumber);
            rbx1.Text = savedNumber.ToString();
            oper = "=";
          
            question.Text += currentNumber;
            currentNumber = 0;
            currentNumber = savedNumber;
 
        }
 
        private void textBox1_TextChanged(object sender, EventArgs e)
        {
           
           
        }
 
        private void textBox1_TextChanged_1(object sender, EventArgs e)
        {
 
        }
 
        private void button2_Click(object sender, EventArgs e)
        {
            if (currentNumber != 0)
            {
                calcOper(ref oper, ref savedNumber, ref currentNumber);
 
                question.Text += currentNumber.ToString() + "+";
                rbx1.Text = savedNumber.ToString();
                currentNumber = 0;
                oper = "+";
            }
        }
 
        private void Form1_Load(object sender, EventArgs e)
        {
 
        }
 
        private void rbx1_TextChanged(object sender, EventArgs e)
        {
 
        }
 
        private void num1_Click(object sender, EventArgs e)
        {
 
            currentNumber = (currentNumber * 10) + 1;
            rbx1.Text = currentNumber.ToString();
           
        }
 
        private void minus_Click(object sender, EventArgs e)
        {
            if (currentNumber != 0)
            {
                calcOper(ref oper, ref savedNumber, ref currentNumber);
                question.Text += currentNumber.ToString() + "-";
                rbx1.Text = savedNumber.ToString();
                currentNumber = 0;
                oper = "-";
            }
        }
       
        private void clear_Click(object sender, EventArgs e)
        {
            rbx1.Clear();
            question.Clear();
            savedNumber = 0;
            currentNumber = 0;
        }
 
        private void mul_Click(object sender, EventArgs e)
        {
            if (currentNumber != 0)
            {
                calcOper(ref oper, ref savedNumber, ref currentNumber);
                question.Text += currentNumber.ToString() + "*";
                rbx1.Text = savedNumber.ToString();
                currentNumber = 0;
                oper = "*";
            }
        }
 
        private void div_Click(object sender, EventArgs e)
        {
            if (currentNumber != 0)
            {
                calcOper(ref oper, ref savedNumber, ref currentNumber);
                question.Text += currentNumber.ToString() + "/";
                rbx1.Text = savedNumber.ToString();
                currentNumber = 0;
                oper = "/";
            }
        }
 
        private void num3_Click(object sender, EventArgs e)
        {
            currentNumber = (currentNumber * 10) + 3;
            rbx1.Text = currentNumber.ToString();
        }
 
        private void num4_Click(object sender, EventArgs e)
        {
            currentNumber = (currentNumber * 10) + 4;
            rbx1.Text = currentNumber.ToString();
        }
 
        private void num5_Click(object sender, EventArgs e)
        {
            currentNumber = (currentNumber * 10) + 5;
            rbx1.Text = currentNumber.ToString();
        }
 
        private void num6_Click(object sender, EventArgs e)
        {
            currentNumber = (currentNumber * 10) + 6;
            rbx1.Text = currentNumber.ToString();
        }
 
        private void num7_Click(object sender, EventArgs e)
        {
            currentNumber = (currentNumber * 10) + 7;
            rbx1.Text = currentNumber.ToString();
        }
 
        private void num8_Click(object sender, EventArgs e)
        {
            currentNumber = (currentNumber * 10) + 8;
            rbx1.Text = currentNumber.ToString();
        }
 
        private void num9_Click(object sender, EventArgs e)
        {
            currentNumber = (currentNumber * 10) + 9;
            rbx1.Text = currentNumber.ToString();
        }
 
        private void num0_Click(object sender, EventArgs e)
        {
            currentNumber = (currentNumber * 10) + 0;
            rbx1.Text = currentNumber.ToString();
        }
 
        private void num2_Click(object sender, EventArgs e)
        {
            currentNumber = (currentNumber * 10) + 2;
            rbx1.Text = currentNumber.ToString();
 
        }
 
        private void question_TextChanged(object sender, EventArgs e)
        {
 
        }
    }
}