# Basic calculator program using C#

To create a calculator program in C#, you need to use Web Forms. Under that create buttons from 1-9, addition, subtraction, multiplication, etc.

Let us see the code for addition, subtraction, and multiplication. Firstly, we have declared two variables −

static float x, y;

Now, we will see how to set codes for calculation on individual button click: Our result textbox is tbResult since we have used Windows Form as well to display the calculator −

protected void add_Click(object sender, EventArgs e) {
x = Convert.ToInt32(tbResult.Text);
tbResult.Text = "";
y = '+';
tbResult.Text += y;
}
protected void sub_Click(object sender, EventArgs e) {
x = Convert.ToInt32(tbResult.Text);
tbResult.Text = "";
y = '-';
tbResult.Text += y;
}
protected void mul_Click(object sender, EventArgs e) {
x = Convert.ToInt32(tbResult.Text);
tbResult.Text = "";
y = '*';
tbResult.Text += y;
}

The following is the equal button code −

protected void eql_Click(object sender, EventArgs e) {
z = Convert.ToInt32(tbResult.Text);
tbResult.Text = "";
if (y == '/') {
p = x / z;
tbResult.Text += p;
x = d;
} else if (y == '+') {
p = x + z;
tbResult.Text += p;
a = d;
} else if (y == '-') {
p = x - z;
tbResult.Text += p;
x = p;
} else {
p = x * z;
tbResult.Text += p;
x = p;
}
}