# Basic Calculator in C#

Here is a procedure to create a basic calculator. In this section I will build a basic calculator that can perform the following operations:

• Subtraction
• Multiplication
• Division
• Clear

Steps:

Open Microsoft Visual Studio 2010 then click on "File"  -> "New"  -> "Website".

Then select "ASP.NET Empty Website".

Then select "Web Form":

And click "Add". Now it will open the page as in the following:

Here we will write our code:.

Process to create calculator

First we need to create a TextBox and 16 Buttons
as in the following:

• 10 Buttons for numbers (0-9)
• 5 Buttons to perform operation (addition (+), Subtraction (-) , Multiplication (*), Division (/) ,Clear (CLR) )
• 1 Buttons for evaluation (=)

Here is the code for the "Default.aspx" page:

<html xmlns="http://www.w3.org/1999/xhtml">

<title></title>

<style type="text/css">

.cal

{

position:absolute;

top:50px;

left:150px;

right:400px;

height:500px;

bottom:100px;

background-color:Teal;

}

</style>

<body>

<form id="form1" runat="server">

<div class="cal">

<asp:Label ID="l" Text=" BASIC CALCULATOR" runat="server" Style="margin-left: 200px"

Font-Bold="False" Font-Italic="False"></asp:Label>

<asp:TextBox ID="t" runat="server" Style="margin-left: 100px; margin-top: 24px;"

Width="335px" Height="41px"></asp:TextBox>

<asp:Button ID="b1" Text="1" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="b1_Click" />

<asp:Button ID="b2" Text="2" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="b2_Click" />

<asp:Button ID="b3" Text="3" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="b3_Click" />

<asp:Button ID="add" Text="+" runat="server" Height="37px" Style="margin-left: 0px;

<asp:Button ID="b4" Text="4" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="b4_Click" />

<asp:Button ID="b5" Text="5" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="b5_Click" />

<asp:Button ID="b6" Text="6" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="b6_Click" />

<asp:Button ID="sub" Text="-" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="sub_Click" />

<asp:Button ID="b7" Text="7" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="b7_Click" />

<asp:Button ID="b8" Text="8" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="b8_Click" />

<asp:Button ID="b9" Text="9" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="b9_Click" />

<asp:Button ID="mul" Text="*" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="mul_Click" />

<asp:Button ID="b0" runat="server" Text="0" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="b0_Click" />

<asp:Button ID="clr" runat="server" Text="CLR" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="clr_Click" />

<asp:Button ID="eql" runat="server" Text="=" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="eql_Click" />

<asp:Button ID="div" Text="/" runat="server" Height="37px" Style="margin-left: 0px"

Width="57px" OnClick="div_Click" />

</div>

</form>

</body>

</html>

Here is the code for the "Default.aspx.cs" page (the code for all the buttons) :

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page

{

static float a, c, d;

static char b;

protected void Page_Load(object sender, EventArgs e)

{

}

protected void b1_Click(object sender, EventArgs e)

{

if ((t.Text == "+") || (t.Text == "-") || (t.Text == "*") || (t.Text == "/"))

{

t.Text = "";

t.Text = t.Text + b1.Text;

}

else

t.Text = t.Text + b1.Text;

}

protected void b2_Click(object sender, EventArgs e)

{

if ((t.Text == "+") || (t.Text == "-") || (t.Text == "*") || (t.Text == "/"))

{

t.Text = "";

t.Text = t.Text + b2.Text;

}

else

t.Text = t.Text + b2.Text;

}

protected void b3_Click(object sender, EventArgs e)

{

if ((t.Text == "+") || (t.Text == "-") || (t.Text == "*") || (t.Text == "/"))

{

t.Text = "";

t.Text = t.Text + b3.Text;

}

else

t.Text = t.Text + b3.Text;

}

protected void b4_Click(object sender, EventArgs e)

{

if ((t.Text == "+") || (t.Text == "-") || (t.Text == "*") || (t.Text == "/"))

{

t.Text = "";

t.Text = t.Text + b4.Text;

}

else

t.Text = t.Text + b4.Text;

}

protected void b5_Click(object sender, EventArgs e)

{

if ((t.Text == "+") || (t.Text == "-") || (t.Text == "*") || (t.Text == "/"))

{

t.Text = "";

t.Text = t.Text + b5.Text;

}

else

t.Text = t.Text + b5.Text;

}

protected void b6_Click(object sender, EventArgs e)

{

if ((t.Text == "+") || (t.Text == "-") || (t.Text == "*") || (t.Text == "/"))

{

t.Text = "";

t.Text = t.Text + b6.Text;

}

else

t.Text = t.Text + b5.Text;

}

protected void b7_Click(object sender, EventArgs e)

{

if ((t.Text == "+") || (t.Text == "-") || (t.Text == "*") || (t.Text == "/"))

{

t.Text = "";

t.Text = t.Text + b7.Text;

}

else

t.Text = t.Text + b7.Text;

}

protected void b8_Click(object sender, EventArgs e)

{

if ((t.Text == "+") || (t.Text == "-") || (t.Text == "*") || (t.Text == "/"))

{

t.Text = "";

t.Text = t.Text + b8.Text;

}

else

t.Text = t.Text + b8.Text;

}

protected void b9_Click(object sender, EventArgs e)

{

if ((t.Text == "+") || (t.Text == "-") || (t.Text == "*") || (t.Text == "/"))

{

t.Text = "";

t.Text = t.Text + b9.Text;

}

else

t.Text = t.Text + b9.Text;

}

protected void b0_Click(object sender, EventArgs e)

{

if ((t.Text == "+") || (t.Text == "-") || (t.Text == "*") || (t.Text == "/"))

{

t.Text = "";

t.Text = t.Text + b0.Text;

}

else

t.Text = t.Text + b0.Text;

}

protected void add_Click(object sender, EventArgs e)

{

a = Convert.ToInt32(t.Text);

t.Text = "";

b = '+';

t.Text += b;

}

protected void sub_Click(object sender, EventArgs e)

{

a = Convert.ToInt32(t.Text);

t.Text = "";

b = '-';

t.Text += b;

}

protected void mul_Click(object sender, EventArgs e)

{

a = Convert.ToInt32(t.Text);

t.Text = "";

b = '*';

t.Text += b;

}

protected void div_Click(object sender, EventArgs e)

{

a = Convert.ToInt32(t.Text);

t.Text = "";

b = '/';

t.Text += b;

}

protected void eql_Click(object sender, EventArgs e)

{

c = Convert.ToInt32(t.Text);

t.Text = "";

if (b == '/')

{

d = a / c;

t.Text += d;

a = d;

}

else if (b == '+')

{

d = a + c;

t.Text += d;

a = d;

}

else if (b == '-')

{

d = a - c;

t.Text += d;

a = d;

}

else

{

d = a * c;

t.Text += d;

a = d;

}

}

protected void clr_Click(object sender, EventArgs e)

{

t.Text = "";

}

}

The final output looks as in the following: