Calculator in C# (Windows Application)

Description

This is a simple calculator program that was written using Visual Studio.NET and C#.  The calculator is a good program to learn how to use mouse and keyboard events. To use this code, create a new C# Windows Application project and  paste this code in.

Source Code:

// Source Code starts
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
namespace Calculator1
{
/// <summary>
/// This is a simple calculator program.
/// Author: David Kulbok
/// Date: 10/16/01
/// Email: [email protected]
///
/// This is my first venture into C# so some of the techniques might seem quick and dirty.
/// If there is a more efficient way of doing something (i.e. Making sure that hitting Enter
/// fires doEquals()) please let me know. I hope that you will learn as much from this
/// program as I did about C# controls and events.
///
/// David Kulbok
///
/// </summary>
public class Calculator1 : System.Windows.Forms.Form
{
#region Constructor
public Calculator1()
{
//
// Required for Windows Form Designer support
//
InitializeComponent();
}
#endregion
#region Global Variables
private System.Windows.Forms.Button btnAdd;
public System.Windows.Forms.TextBox txtResult;
private System.Windows.Forms.Button btn1;
private System.Windows.Forms.Button btn2;
private System.Windows.Forms.Button btn3;
private System.Windows.Forms.Button btn4;
private System.Windows.Forms.Button btn5;
private System.Windows.Forms.Button btn6;
private System.Windows.Forms.Button btn7;
private System.Windows.Forms.Button btn8;
private System.Windows.Forms.Button btn9;
private System.Windows.Forms.Button btn0;
private System.Windows.Forms.Button btnSubtract;
private System.Windows.Forms.Button btnMultiply;
private System.Windows.Forms.Button btnDivide;
private System.Windows.Forms.Button btnEquals;
private System.Windows.Forms.Button btnClear;
private System.Windows.Forms.Button btnNegative;
private System.Windows.Forms.Button btnDecimal;
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.Container components = null;
/// <summary>
/// These are global variables defined for use in the calculator
/// <summary>
private int opMain = 0; /// Stores the value of the operation (1-4)
private double mainNum1 = 0; ///Stores the value of the first number
private double mainNum2 = 0; ///Stores the value of the second number
private bool isSecond = false; //Boolean value used to determine if input is the second or first number.
private bool isDone = false; ///Boolean value used to determine if the equals key was pressed.
private bool isDecimal = false; //Boolean value used to determine if there is a decimal in the number.
#endregion
#region Dispose
/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}
#endregion
#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// Most of these just set the controls and the properties for them. There are some event handlers that I will explain as I go along.
/// <summary>
private void InitializeComponent()
{
this.btn2 = new System.Windows.Forms.Button();
this.btn3 = new System.Windows.Forms.Button();
this.btn0 = new System.Windows.Forms.Button();
this.btn1 = new System.Windows.Forms.Button();
this.btn6 = new System.Windows.Forms.Button();
this.btn7 = new System.Windows.Forms.Button();
this.btn4 = new System.Windows.Forms.Button();
this.btnDivide = new System.Windows.Forms.Button();
this.btn9 = new System.Windows.Forms.Button();
this.btnAdd = new System.Windows.Forms.Button();
this.btnSubtract = new System.Windows.Forms.Button();
this.btnDecimal = new System.Windows.Forms.Button();
this.btnClear = new System.Windows.Forms.Button();
this.txtResult = new System.Windows.Forms.TextBox();
this.btnMultiply = new System.Windows.Forms.Button();
this.btn5 = new System.Windows.Forms.Button();
this.btn8 = new System.Windows.Forms.Button();
this.btnEquals = new System.Windows.Forms.Button();
this.btnNegative = new System.Windows.Forms.Button();
this.SuspendLayout();
//
// btn2
//
this.btn2.ForeColor = System.Drawing.Color.FromArgb(((System.Byte)(0)),((System.Byte)(0)),((System.Byte)(192)));
this.btn2.Location = new System.Drawing.Point(48, 40);
this.btn2.Name = "btn2";
this.btn2.Size = new System.Drawing.Size(32, 32);
this.btn2.TabIndex = 13;
this.btn2.TabStop = false;
this.btn2.Text = "2";
this.btn2.Click += new System.EventHandler(this.btn2_Click);
//
// btn3
//
this.btn3.ForeColor = System.Drawing.Color.FromArgb(((System.Byte)(0)),((System.Byte)(0)),((System.Byte)(192)));
this.btn3.Location = new System.Drawing.Point(88, 40);
this.btn3.Name = "btn3";
this.btn3.Size = new System.Drawing.Size(32, 32);
this.btn3.TabIndex = 12;
this.btn3.TabStop = false;
this.btn3.Text = "3";
this.btn3.Click += new System.EventHandler(this.btn3_Click);
//
// btn0
//
this.btn0.ForeColor = System.Drawing.Color.FromArgb(((System.Byte)(0)),((System.Byte)(0)), ((System.Byte)(192)));
this.btn0.Location = new System.Drawing.Point(48, 160);
this.btn0.Name = "btn0";
this.btn0.Size = new System.Drawing.Size(32, 32);
this.btn0.TabIndex = 5;
this.btn0.TabStop = false;
this.btn0.Text = "0";
this.btn0.Click += new System.EventHandler(this.btn0_Click);
//
// btn1
//
this.btn1.ForeColor = ystem.Drawing.Color.FromArgb(((System.Byte)(0)),((System.Byte)(0)),((System.Byte)(192)));
this.btn1.Location = new System.Drawing.Point(8, 40);
this.btn1.Name = "btn1";
this.btn1.Size = new System.Drawing.Size(32, 32);
this.btn1.TabIndex = 14;
this.btn1.TabStop = false;
this.btn1.Text = "1";
this.btn1.Click += new System.EventHandler(this.btn1_Click_1);
//
// btn6
//
this.btn6.ForeColor = System.Drawing.Color.FromArgb(((System.Byte)(0)),((System.Byte)(0)),((System.Byte)(192)));
this.btn6.Location = new System.Drawing.Point(88, 80);
this.btn6.Name = "btn6";
this.btn6.Size = new System.Drawing.Size(32, 32);
this.btn6.TabIndex = 9;
this.btn6.TabStop = false;
this.btn6.Text = "6";
this.btn6.Click += new System.EventHandler(this.btn6_Click);
//
//btn7
//
this.btn7.ForeColor = System.Drawing.Color.FromArgb(((System.Byte)(0)),((System.Byte)(0)),((System.Byte)(192)));
this.btn7.Location = new System.Drawing.Point(8, 120);
this.btn7.Name = "btn7";
this.btn7.Size = new System.Drawing.Size(32, 32);
this.btn7.TabIndex = 8;
this.btn7.TabStop = false;
this.btn7.Text = "7";
this.btn7.Click += new System.EventHandler(this.btn7_Click);
//
// btn4
//
this.btn4.ForeColor = System.Drawing.Color.FromArgb(((System.Byte)(0)),((System.Byte)(0)),((System.Byte)(192)));
this.btn4.Location = new System.Drawing.Point(8, 80);
this.btn4.Name = "btn4";
this.btn4.Size = new System.Drawing.Size(32, 32);
this.btn4.TabIndex = 11;
this.btn4.TabStop = false;
this.btn4.Text = "4";
this.btn4.Click += new System.EventHandler(this.btn4_Click);
//
// btnDivide
//
this.btnDivide.Location = new System.Drawing.Point(136, 160);
this.btnDivide.Name = "btnDivide";
this.btnDivide.Size = new System.Drawing.Size(32, 32);
this.btnDivide.TabIndex = 2;
this.btnDivide.TabStop = false;
this.btnDivide.Text = "/";
this.btnDivide.Click += new System.EventHandler(this.btnDivide_Click);
//
// btn9
//
this.btn9.ForeColor = System.Drawing.Color.FromArgb(((System.Byte)(0)),((System.Byte)(0)),((System.Byte)(192)));
this.btn9.Location = new System.Drawing.Point(88, 120);
this.btn9.Name = "btn9";
this.btn9.Size = new System.Drawing.Size(32, 32);
this.btn9.TabIndex = 6;
this.btn9.TabStop = false;
this.btn9.Text = "9";
this.btn9.Click += new System.EventHandler(this.btn9_Click);
//
// btnAdd
//
this.btnAdd.Location = new System.Drawing.Point(136, 40);
this.btnAdd.Name = "btnAdd";
this.btnAdd.Size = new System.Drawing.Size(32, 32);
this.btnAdd.TabIndex = 15;
this.btnAdd.TabStop = false;
this.btnAdd.Text = "+";
this.btnAdd.Click += new System.EventHandler(this.btnAdd_Click);
//
// btnSubtract
//
this.btnSubtract.Location = new System.Drawing.Point(136, 80);
this.btnSubtract.Name = "btnSubtract";
this.btnSubtract.Size = new System.Drawing.Size(32, 32);
this.btnSubtract.TabIndex = 4;
this.btnSubtract.TabStop = false;
this.btnSubtract.Text = "-";
this.btnSubtract.Click += new System.EventHandler(this.btnSubtract_Click);
//
// btnDecimal
//
this.btnDecimal.Location = new System.Drawing.Point(88, 200);
this.btnDecimal.Name = "btnDecimal";
this.btnDecimal.Size = new System.Drawing.Size(32, 32);
this.btnDecimal.TabIndex = 17;
this.btnDecimal.TabStop = false;
this.btnDecimal.Text = ".";
this.btnDecimal.Click += new System.EventHandler(this.btnDecimal_Click);
//
// btnClear
//
this.btnClear.ForeColor = System.Drawing.Color.Red;
this.btnClear.Location = new System.Drawing.Point(8, 200);
this.btnClear.Name = "btnClear";
this.btnClear.Size = new System.Drawing.Size(32, 32);
this.btnClear.TabIndex = 0;
this.btnClear.TabStop = false;
this.btnClear.Text = "C";
this.btnClear.Click += new System.EventHandler(this.btnClear_Click);
//
// txtResult
//
this.txtResult.Location = new System.Drawing.Point(8, 8);
this.txtResult.Name = "txtResult";
this.txtResult.RightToLeft = System.Windows.Forms.RightToLeft.No;
this.txtResult.Size = new System.Drawing.Size(160, 20);
this.txtResult.TabIndex = 15;
this.txtResult.TabStop = false;
this.txtResult.Text = "";
this.txtResult.TextAlign = System.Windows.Forms.HorizontalAlignment.Right;
//
// btnMultiply
//
this.btnMultiply.Location = new System.Drawing.Point(136, 120);
this.btnMultiply.Name = "btnMultiply";
this.btnMultiply.Size = new System.Drawing.Size(32, 32);
this.btnMultiply.TabIndex = 3;
this.btnMultiply.TabStop = false;
this.btnMultiply.Text = "*";
this.btnMultiply.Click += new System.EventHandler(this.btnMultiply_Click);
//
// btn5
//
this.btn5.ForeColor = System.Drawing.Color.FromArgb(((System.Byte)(0)),((System.Byte)(0)),((System.Byte)192)));
this.btn5.Location = new System.Drawing.Point(48, 80);
this.btn5.Name = "btn5";
this.btn5.Size = new System.Drawing.Size(32, 32);
this.btn5.TabIndex = 10;
this.btn5.TabStop = false;
this.btn5.Text = "5";
this.btn5.Click += new System.EventHandler(this.btn5_Click);
//
// btn8
//this.btn8.ForeColor = System.Drawing.Color.FromArgb(((System.Byte)(0)),((System.Byte)(0)),((System.Byte)(192)));
this.btn8.Location = new System.Drawing.Point(48, 120);
this.btn8.Name = "btn8";
this.btn8.Size = new System.Drawing.Size(32, 32);
this.btn8.TabIndex = 7;
this.btn8.TabStop = false;
this.btn8.Text = "8";
this.btn8.Click += new System.EventHandler(this.btn8_Click);
//
// btnEquals
//
this.btnEquals.Location = new System.Drawing.Point(136, 200);
this.btnEquals.Name = "btnEquals";
this.btnEquals.Size = new System.Drawing.Size(32, 32);
this.btnEquals.TabIndex = 1;
this.btnEquals.TabStop = false;
this.btnEquals.Text = "=";
this.btnEquals.Click += new System.EventHandler(this.btnEquals_Click);
//
// btnNegative
//
this.btnNegative.Location = new System.Drawing.Point(48, 200);
this.btnNegative.Name = "btnNegative";
this.btnNegative.Size = new System.Drawing.Size(32, 32);
this.btnNegative.TabIndex = 16;
this.btnNegative.TabStop = false;
this.btnNegative.Text = "+/-";
this.btnNegative.Click += new System.EventHandler(this.btnNegative_Click);
//
// Calculator1
//
this.AcceptButton = this.btnEquals;
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.ClientSize = new System.Drawing.Size(176, 245);
this.Controls.AddRange(new System.Windows.Forms.Control[]
{this.btnDecimal,
this.btnNegative,
this.btnClear,
this.btnEquals,
this.btnDivide,
this.btnMultiply,
this.btnSubtract,
this.btn0,
this.btn9,
this.btn8,
this.btn7,
this.btn6,
this.btn5,
this.btn4,
this.btn3,
this.btn2,
this.btn1,
this.txtResult,
this.btnAdd});
this.KeyPreview = true;
this.Name = "Calculator1";
this.Text = "Calculator";
this.KeyDown += new System.Windows.Forms.KeyEventHandler(this.Btn_KeyDown);
this.ResumeLayout(false);
}
#endregion
///Custom Methods
#region setText(String textset)
/// <summary>
/// This method is used to set the text in the textbox to the number entered by the user.
/// <summary>
/// <param name="textset"></param>
public void setText(String textset)
{
if(textset.Equals("clear"))
//If the user hits the clear button
txtResult.Text = ""; //Clear the text and reset the boolean variables.
isDone = false;
isSecond = false;
isDecimal = false;
}
else
{
if(isSecond) //Determine if the number being entered is the begining of the second number.If it is:
{
txtResult.Text = textset;
//Start the text over and set the first # to what the user enters
isSecond = false; //So Calculator knows to continue the # rather than making a new one.
isDecimal = false;
}
else
{
if(isDone) //isDone lets the program know that the user just hit "=" and if they press another # to start a new number.
{
txtResult.Text = textset;
isDone=false; //Set isDone to false so that the number just started is added on to and a new # is not started.
}
else
txtResult.Text += textset; //Simply add on to the existing #.
}
}
btnEquals.Select();
//Set the focus back to the "=" button.
}
#endregion
#region Calc(double num1, double num2, int op)
/// <summary>
/// Calc takes the 2 numbers and the operation and calcualtes the answer.
/// <summary>
/// <param name="num1"></param>
/// <param name="num2"></param>
/// <param name="op"></param>
public void Calc(double num1, double num2, int op)
{
double answer = 0;//Initialize answer to 0;
switch(op) //Determine which operation to perform depending on the value of "op"
{
case1:| answer = num1 + num2;
break;
case 2:
answer = num1 - num2;
break;
case 3:
answer = num1 * num2;
break;
case 4:
answer = num1 / num2;
break;
}
setText(answer.ToString()); //Show the answer in the textbox;
}
#endregion
#region doEquals()
/// <summary>
/// This method stores the second number, clears the textbox and calls the Calc method
/// </summary>
private void doEquals()
{
mainNum2 =double.Parse(txtResult.Text);
//Set the value of the second number
setText("clear"); //Clear the textbox
Calc(mainNum1, mainNum2,opMain); //Call the Calc method
isDone = true; //Set isDone to true so that if another # is pressed, the program will begin a new number
}
#endregion
#region changeSign()
/// <summary>
/// This method changes the sign of the number. If the number is positive
/// it makes it negative and vice versa.
/// </summary>
private void changeSign()
{
double storNum; //Variable to store value of number
if(txtResult.Text.Length > 0) //If there is a number...
{
storNum = double.Parse(txtResult.Text); //Store its value
storNum *= -1; //multiply by negative 1
txtResult.Text = storNum.ToString(); //put it in the textbox.
}
btnEquals.Select(); //Set focus to "=" button
}
#endregion
#region setOperator(int operation)
/// <summary>
/// The method is used to store the first number and the operation being performed.
/// <summary>
// <param name="operation"></param>
private void setOperator(int operation)
{
if(txtResult.Text.Length > 0)//Make sure that the user entered a number
{
opMain = operation; //Store the operation
mainNum1 = double.Parse(txtResult.Text); //Store the value of the first number
isSecond = true; //Let the program know to begin the second number
isDone = false; //If a operator button is pressed before a new number, let the program know to start a new umber.
btnEquals.Select(); //Set the focus to the equals button.
}
}
#endregion
#region setDecimal()
/// <summary>
/// This method checks to see if the # has a decimal in it. If not, it
/// puts one in. If it does, no decimal is entered.
/// </summary>
private void setDecimal()
{
if(!isDecimal)//Check for existing decimal
{
setText("."); //Add decimal
isDecimal = true; //Let program know decimal has been added
}
btnEquals.Select(); //Set focus to "=" button
}
#endregion
#region KeyBoard Events
/// <summary>
/// This method simply determines which key is being pressed.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void Btn_KeyDown (object sender,KeyEventArgs e)
{
//MessageBox.Show(e.KeyValue.ToString());
filterKeys(e.KeyValue);
}
/// <summary>
/// This method accepts the value of the key and calls the corresponding methods.
/// It is pretty self-explanatory.
/// </summary>
/// <param name="keyCode"></param>
public void filterKeys(int keyCode)
{
switch(keyCode)
{
case 96:
setText("0");
break;
case 97:
setText("1");
break;
case 98:
setText("2");
break;
case 99:
setText("3");
break;
case 100:
setText("4");
break;
case 101:
setText("5");
break;
case 102:
setText("6");
break;
case 103:
setText("7");
break;
case 104:
setText("8");
break;
case 105:
setText("9");
break;
case 67:
setText("clear");
break;
case 107:
setOperator(1);
break;
case 109:
setOperator(2);
break;
case 106:
setOperator(3);
break;
case 111:
setOperator(4);
break;
case 110:
setDecimal();
break;
}
}
#endregion
#region Button Functions
///These methods do the same as when a key is pressed except the respond to the
///mouse clicks on the different controls. These are the methods that were mapped to
///the controls up top.
private void btnAdd_Click(object sender,System.EventArgs e)
{
setOperator(1);
}
private void btn1_Click_1(object sender,System.EventArgs e)
{
setText("1");
}
private void btn2_Click(object sender,System.EventArgs e)
{
setText("2");
}
private void btn3_Click(object sender,System.EventArgs e)
{
setText("3");
}
private void btn4_Click(object sender,System.EventArgs e)
{
setText("4");
}
private void btn5_Click(object sender,System.EventArgs e)
{
setText("5");
}
private void btn6_Click(object sender,System.EventArgs e)
{
setText("6");
}
private void btn7_Click(object sender,System.EventArgs e)
{
setText("7");
}
private void btn8_Click(object sender,System.EventArgs e)
{
setText("8");
}
private void btn9_Click(object sender,System.EventArgs e)
{
setText("9");
}
private void btn0_Click(object sender,System.EventArgs e)
{
setText("0");
}
private void btnEquals_Click(object sender,System.EventArgs e)
{
doEquals();
}
private void btnClear_Click(object sender,System.EventArgs e)
{
isSecond = false;
setText("clear");
}
private void btnSubtract_Click(object sender,System.EventArgs e)
{
setOperator(2);
}
private void btnMultiply_Click(object sender,System.EventArgs e)
{
setOperator(3);
}
private void btnDivide_Click(object sender,System.EventArgs e)
{
setOperator(4);
}
private void btnNegative_Click(object sender,System.EventArgs e)
{
changeSign();
}
private void btnDecimal_Click(object sender,System.EventArgs e)
{
setDecimal();
}
#endregion
#region Main()
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
deApplication.Run(new Calculator1());
}
#endregion
}nevermind
}
// Source Code End