 Simple Calculator Using A Class In C# | Free Source Code

# Simple Calculator using a Class in C# This is a tutorial wherein I will be teaching you how to create a program in C# that will compute sum, difference, quotient, and product as just a simple calculator that uses a class.

Let’s start this tutorial!

1. Start with creating a Windows Form Application in C# for this tutorial by following the following steps in Microsoft Visual Studio 2019: Go to File, click New Project, and choose Windows Application. 3. Create a class named calculate and put this code below.

```using System.Diagnostics;
using System;
using System.Xml.Linq;
using System.Windows.Forms;
using System.Collections;
using System.Drawing;
using System.Data;
using System.Collections.Generic;
using System.Linq;

namespace MDAS
{
public class calculate
{
//declare a private variable as a double
private double _num1;
private double _num2;
private double _total;

//set a readonly property for the total of the MDAS
public double total
{
get
{
return _total; //return the total
}
}
//create a property for a private variable so that you can access it
public double num1
{
get
{
return _num1; //return the first value
}
set
{
_num1 = value; //set the first value
}
}
public double num2
{
get
{
return _num2;
}
set
{
_num2 = value;
}
}

//create the sub procedures of the MDAS
public void multiply()
{
//formula of multiplication
_total = num1 * num2;
}
public void divide()
{
//formula of division
_total = num1 / num2;
}
{
_total = num1 + num2;
}
public void subtract()
{
//formula of subtraction
_total = num1 - num2;
}

}

}```

4. Now, go to your Form and put this code below for the calculator operation.

```using System.Diagnostics;
using System;
using System.Xml.Linq;
using System.Windows.Forms;
using System.Collections;
using System.Drawing;
using System.Data;
using System.Collections.Generic;
using System.Linq;

namespace MDAS
{
public partial class Form1
{
public Form1()
{
InitializeComponent();
}

//create a sub procedure for the events of clicking the radio button that handles all of it.
public void RadioButton_Click(object sender, System.EventArgs e)
{

//call a constructor method and return to cal as an instance of a class
calculate cal = new calculate();

//declaring the string variable represent as a textbox
string txtnum1 = TextBox1.Text;
string txtnum2 = TextBox2.Text;
//declaring the double variable
double dbl_val1 = default(double);
double dbl_val2 = default(double);

if (Information.IsNumeric(txtnum1) && Information.IsNumeric(txtnum2)) //check if the textbox has a numeric value
{
//convert the string to double
dbl_val1 = double.Parse(txtnum1);
dbl_val2 = double.Parse(txtnum2);

//get the value of the converted variable
//to pass it into the variable in the class
cal.num1 = dbl_val1;
cal.num2 = dbl_val2;

//the condition is, if the radiobutton is clicked,
//the operation of MDAS executes.
{
//result:
cal.multiply(); //call a subname in a class for multiplying
}
{
//result:
cal.divide(); //call a subname in a class for dividing
}
{
//result:
}
{
//result:
cal.subtract(); //call a subname in a class for subtracting
}
}
else
{
//the result is:
//if the textbox is empty or has a string value
TextBox3.Text = "Enter a number";
return ;
}
//put the result of the MDAS to a textbox.
TextBox3.Text = cal.total.ToString();
}

}

}```

Output: 