using System.Collections.Generic;
using System.ComponentModel;
using System.Windows.Forms;
public partial class Form1 : Form
this.txtResult.Text = "";
this.lbResult.Text = "Ready";
private void btnAdd_Click(object sender, EventArgs e)
double num1 = double.Parse(this.txtNum1.Text);
double num2 = double.Parse(this.txtNum2.Text);
double num = num1 + num2;
this.txtResult.Text = num.ToString();
thils.lbResult.Text = "+";
private void btnClear(object sender, EventArgs e)
this.txtResult.Text = "";
this.lbResult.Text = "Ready";