title: Add to int each time a button is clicked and show in textbox c#
body: <p>I am very new to programming and I am trying to do that every time you click a button, it adds one to the value of an <code>int</code> and shows it in a <strong>textbox</strong>. My code is:</p>
  
  <pre><code>private void button1_Click(object sender, EventArgs e)
  {
      int a = 100;
      a++;
  
      txtBox1.Text = a.ToString();
  }
  </code></pre>
  
  <p>So when I click the button it shows in the text box 101, but when I click it again, I want the textbox to show 102 and 103 etc etc. Any ideas? I assume it's very easy and using some variation of a loop but I have tried a few things and nothing seems to work. Any tips would be greatly appreciated! Thanks.</p>