[C#] Simple Calculator Source

[Elite_Modz]

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 WindowsFormsApplication2_Login_
{
  public partial class Calculator : Form
  {
  public Calculator()
  {
  InitializeComponent();
  }

  public void disable()
  {
  button13.Hide();
  button1.Show();
  button20.Enabled = false;
  button19.Enabled = false;
  button18.Enabled = false;
  button17.Enabled = false;
  button16.Enabled = false;
  button15.Enabled = false;
  button14.Enabled = false;
  button13.Enabled = false;
  button12.Enabled = false;
  button11.Enabled = false;
  button10.Enabled = false;
  button9.Enabled = false;
  button8.Enabled = false;
  button7.Enabled = false;
  button6.Enabled = false;
  button5.Enabled = false;
  button4.Enabled = false;
  button3.Enabled = false;
  button2.Enabled = false;
  }

  public void enable()
  {
  button1.Hide();
  button13.Show();
  button20.Enabled = true;
  button19.Enabled = true;
  button18.Enabled = true;
  button17.Enabled = true;
  button16.Enabled = true;
  button15.Enabled = true;
  button14.Enabled = true;
  button12.Enabled = true;
  button11.Enabled = true;
  button10.Enabled = true;
  button9.Enabled = true;
  button8.Enabled = true;
  button7.Enabled = true;
  button6.Enabled = true;
  button5.Enabled = true;
  button4.Enabled = true;
  button2.Enabled = true;
  }

  float num, ans;
  int count;

  public void compute()
  {
  switch(count)
  {
  case 1:
  ans = num + float.Parse(textBox1.Text);
  textBox1.Text = ans.ToString();
  break;

  case 2:
  ans = num - float.Parse(textBox1.Text);
  textBox1.Text = ans.ToString();
  break;

  case 3:
  ans = num / float.Parse(textBox1.Text);
  textBox1.Text = ans.ToString();
  break;

  case 4:
  ans = num * float.Parse(textBox1.Text);
  textBox1.Text = ans.ToString();
  break;

  }
  }

  private void button17_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + 0;
  textBox1.ForeColor = Color.Red;
  }

  private void button18_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + ".";
  textBox1.ForeColor = Color.Red;
  }

  private void button14_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + 1;
  textBox1.ForeColor = Color.Red;
  }

  private void button15_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + 2;
  textBox1.ForeColor = Color.Red;
  }

  private void button16_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + 3;
  textBox1.ForeColor = Color.Red;
  }

  private void button9_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + 4;
  textBox1.ForeColor = Color.Red;
  }

  private void button10_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + 5;
  textBox1.ForeColor = Color.Red;
  }

  private void button11_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + 6;
  textBox1.ForeColor = Color.Red;
  }

  private void button5_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + 7;
  textBox1.ForeColor = Color.Red;
  }

  private void button6_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + 8;
  textBox1.ForeColor = Color.Red;
  }

  private void button7_Click(object sender, EventArgs e)
  {
  textBox1.Text = textBox1.Text + 9;
  textBox1.ForeColor = Color.Red;
  }

  private void button1_Click(object sender, EventArgs e)//On Button
  {
  enable();
  }

  private void button13_Click(object sender, EventArgs e)//Off Button
  {
  disable();
  }

  private void button4_Click(object sender, EventArgs e)
  {
  num = float.Parse(textBox1.Text);
  textBox1.Clear();
  textBox1.Focus();
  count = 1;
  label1.Text = num.ToString() + "+";
  }

  private void button8_Click(object sender, EventArgs e)
  {
  num = float.Parse(textBox1.Text);
  textBox1.Clear();
  textBox1.Focus();
  count = 1;
  label1.Text = num.ToString() + "-";
  }

  private void button3_Click(object sender, EventArgs e)
  {
  num = float.Parse(textBox1.Text);
  textBox1.Clear();
  textBox1.Focus();
  count = 1;
  label1.Text = num.ToString() + "*";
  }

  private void button12_Click(object sender, EventArgs e)
  {
  num = float.Parse(textBox1.Text);
  textBox1.Clear();
  textBox1.Focus();
  count = 1;
  label1.Text = num.ToString() + "/";
  }

  private void button19_Click(object sender, EventArgs e)
  {
  compute();
  label1.Text = "";
  }

  private void button20_Click(object sender, EventArgs e)
  {
  textBox1.Text = "";
  }

  private void button2_Click(object sender, EventArgs e)
  {
  int lenght = textBox1.TextLength - 1;
  string text = textBox1.Text;
  textBox1.Clear();
  for (int i = 0; i < lenght; i++)
  textBox1.Text = textBox1.Text + text[i];
  }
  }
}

 

[V21Dangerous_]

Thanks giving it a try