code:
import library:
using System.Data;
inside the form class:
private string currentCalculation = "";
create following function:
1. for button text extraction
private void button_click(object sender, EventArgs e)
{
currentCalculation += (sender as Button).Text;
txtOutput.Text = currentCalculation;
}
2. for calculation
private void button_Equals_click(object sender, EventArgs e)
{
string formattedCalculation = currentCalculation.ToString();
try
{
txtOutput.Text = new DataTable().Compute(formattedCalculation, null).ToString();
currentCalculation = txtOutput.Text;
}
catch(Exception ex)
{
txtOutput.Text = "ERROR";
currentCalculation = "";
}
}
3. for clearing button
private void button_Clear_click(object sender, EventArgs e)
{
txtOutput.Text = "0";
currentCalculation = "";
}
4. for clearing entry button
private void button_clearEntery_click(object sender, EventArgs e)
{
if (currentCalculation.Length > 0)
{
//1+1
currentCalculation = currentCalculation.Remove(currentCalculation.Length - 1, 1);
}
txtOutput.Text = currentCalculation;
}
call these function in respective button clicking event!