calculator_app.java

a calculator applet developed in java to perform mathematical calculations

import java.awt.*;
import java.util.*;
import java.awt.event.*;
import java.applet.*;
import java.math.*;
import java.io.*;
import java.lang.*;
import javax.swing.*;

/*
<applet code=Calculator_app.class width =500 height=400>
</applet>
*/

public class Calculator_app extends JApplet implements KeyListener, ActionListener
{
	private File_class f=new File_class();// The File_class class is an inner class. The File_class class consists of methods used  to work with  files.
	private ButtonGroup degree_cont;//To group the two checkbox options.
	private JTextArea textarea1;
	
	private JLabel label1,memoryTagLabel;

	private Button_class[] button;// Declaring variable of Button_class.

	private JTextField textf;// Declaring the text field to the input given. 
	private String str="0",str1="",str2="",op="", str3="";// Declaring the 5 string variable.
	private double m=0,n=0,mem=0;
	private JPanel pa1,pa2,pa3,pa4,pa5,pa6,pa7, pa8;// Declaring the eight variable.
	// Declaring the label for the button.
	private String[] Strbutton={"Power" , "Advanced" ,"Shift","C","CE", "BackSpace" ,"7", "8","9","4","5","6","1","2","3","0",".","Pie", "=","Ans","Sin","Cos","Sqrt","Sqr","X!","Pow" ,"%","1/X","+/-","StartStoring","EndStoring" ,"/", "Del","*","Me","-","M+","+","M-","MR","R","Preview","Close"};
	
	private boolean cond=false,cond1=false, cond2=false,cond3=false,cond4=false,cond5=true,pressed=false;
 

public void init()// Init method is used to initialise the values.
{
  	
	Container contentPane = getContentPane();
  	contentPane.setLayout(new BorderLayout(0,7));
	// Setting the layout as borderlayout. 
//  	contentPane.setBackground(Color.yellow);
	label1=new JLabel(" CALCULATOR ");
	memoryTagLabel=new JLabel(" ");
	memoryTagLabel.setEnabled(true);
	label1.setFont(new Font("Times Roman",Font.BOLD,20));
	memoryTagLabel.setFont(new Font("Times Roman",Font.BOLD,17));
	memoryTagLabel.setForeground(Color.black);
	label1.setForeground(Color.blue);
	textarea1=new JTextArea("Developed\n  By\n Aman ",4,11);
	textarea1.setFont(new Font("Times Roman",Font.BOLD,12));
	textarea1.setEditable(false);
	
	boolean wrap = true; 
	textarea1.setLineWrap(wrap); 
	
	degree_cont = new ButtonGroup();//The container of the checkboxes.
	JRadioButton degrees = new JRadioButton("Deg",true);
	degrees.setActionCommand("Deg");
	//degrees.addItemListener(this);
	JRadioButton radians = new JRadioButton("Rad",false);
	radians.setActionCommand("Rad");
	//radians.addItemListener(this);
	degree_cont.add(degrees);
	degree_cont.add(radians);
	button =new Button_class[43];
	for(int i=0;i<20;i++)//Creating the Advanced buttons such as, sin & cos & arcsin. 			
		button[i]=new Button_class (Strbutton[i],Color.black);
		
		// new Color(55,168,200)
		
	for(int i=20;i<43;i++)//Creating the numbers. 
		button[i]=new Button_class (Strbutton[i],Color.black);
	textf=new JTextField(22);
	textf.setHorizontalAlignment(JTextField.RIGHT );
	textf.setFont(new Font("Times Roman", Font.BOLD,12));
	textf.addKeyListener(this);
	textf.setText("0");
	//Constructs  panels in the applet.
	pa1=new JPanel();
	pa2=new JPanel();
	pa3=new JPanel();
	pa4=new JPanel();
	pa5=new JPanel();
	pa6=new JPanel();
	pa7=new JPanel();
	pa8=new JPanel();
	pa5.setBounds(20,1,275,30);
	pa5.add(button[0]);
	pa5.add(label1);
	contentPane.add(pa5);
	pa3.setLayout(new GridLayout(6,3,2,3));
	pa3.setBounds(20,120,225,156);
	for (int i=3;i<19;i++)
		pa3.add(button[i]);
	contentPane.add(pa3);
	pa1.setLayout(new GridLayout(3,3,2,2));
	pa1.setBounds(20,276,225,78);
	for(int i=20;i<29;i++)
		pa1.add(button[i]); 
	contentPane.add(pa1);
	pa2.setBounds(20,32,300,90);
	pa2.add(textf);
	pa2.add(memoryTagLabel);
	pa2.add(pa4);
	pa4.setBounds(40,50,260,80);
	pa4.add(button[1]);
	pa4.add(button[2]);
	pa4.add(degrees);
	pa4.add(radians); 
	
	textf.setBackground(Color.black);
	contentPane.add(pa2);
    pa7.setBounds(320,1,150,182);
	pa7.add(textarea1);
	pa7.add(button[41]);
	pa7.add(button[42]);
	contentPane.add(pa7);
	pa6.setLayout(new GridLayout(6,2,2,2));
	pa6.setBounds(280,196,200,156);
	pa8.setBounds(0,0,400,40);
	for(int i=29;i<41;i++)
	pa6.add(button[i]);
	contentPane.add(pa6);
	contentPane.add(pa8);
//Before you can use the Calculator you have to press the power button on the calculator interface to enable  buttons on the calculator interface.
	for(int i=1;i<43;i++)
		button[i].setEnabled(false);
	textf.setEditable(false);

	//Adding the action listener.		
	for(int i=0;i<43;i++)
		button[i].addActionListener(this);
	//degrees.addItemListener(this);
	//radians.addItemListener(this); 
}//End of init method.


class Button_class extends JButton
{
	public Button_class(String name, Color xyz) 
	{
		this.setLabel(name);
		this.setForeground(xyz);
	}
}

	
	
 	
	
 	public void keyTyped(KeyEvent e)//Denotes a key press followed by a key release.
 	{
		char ch;
		ch=e.getKeyChar();
		if ((ch=='1')||(ch=='2') || (ch=='3') ||(ch=='4')||
			(ch=='5')||(ch=='6')||(ch=='7')||(ch=='8')||(ch=='9')
			||(ch=='0')) //To check the source label of the pressed key. 
		{   
			if(pressed)
			{
				str="0";
				pressed=false;
			}
			if(str=="0")//Check whether string is empty or not.
				str=""+ch;
			else 
				str=str+ch;
		}//End if. 
		else if(ch=='.'&& cond5)
		{
			if(pressed)
			{
				str="0";
				pressed=false;
			}
			str=str+ch;
			cond5=false;
		}
		else if((ch=='+')||(ch=='-')||(ch=='*') ||(ch=='/'))
		{
			op=""+ch;
			str1=str;
			str="0";
		}
		else if(ch=='=')
			calculate();
		textf.setText(str);
}//End of method declaration KeyTyped().




public void keyPressed(KeyEvent e)//Indicates  a key is pushed down.
{
	double ac=e.getKeyCode();
	if((ac==13)||(ac==10))
		calculate();
	else if(ac==8)
	{
		if(str.compareTo("")==0)
	    	textf.setText("Error");
		else
		{
			str = str.substring(0,str.length()-1);
			textf.setText(str);
		}
	}
}//End of method KeyPressed.

public void keyReleased(KeyEvent e)//Indicates  a key is Released.
{
}


public void actionPerformed(ActionEvent e)//  Action listener method for  buttons on the calculator.
{
	if (e.getSource()==button[29])//For begin store in the file. // " StartStoring" button
	{
		cond4=true;
		button[30].setEnabled(true);// for //button with label StartStoring "EndStoring " Button
		button[29].setEnabled(false);
		f.CreateFile();// Invokes the method for creating a new file.  
}
 	else if (e.getSource()==button[30])//End of the storing. 
	{
		cond4=false;
		button[29].setEnabled(true);
		button[30].setEnabled(false);
		f.endStore();// Call method  for stop storing the file. 
	} 
	else if (e.getSource() == button[41]) //Preview button.
	{
		button[41].setEnabled(false);
		button[42].setEnabled(true);
		f.WriteFileOnTextArea();
	}
	else if (e.getSource()==button[42]) // "Close" Button 
	{
		button[41].setEnabled(true);
		button[42].setEnabled(false);
		textarea1.setText("Developed\n by\n Aman\n" );
	}
	else if (e.getSource()==button[32]) // "Del" Button 
//Del button.
	{
		f.CreateFile();
	}
	else if (e.getSource()==button[1])	  //For advanced buttons.
	{
		if(!cond)
		{
			cond=true;
			pa1.setVisible(true);
			button[1].setLabel("Simple");
			for(int i=20;i<29;i++)
			button[i].setEnabled(true);
		}
		else
		{
			button[1].setLabel("Advanced" );
			pa1.setVisible(false);
			cond=false;
		}
	}
	
	else if(e.getSource()==button[20])
	{
		pressed=true;
		double x=Double.valueOf(str).doubleValue();
		String str4 = degree_cont.getSelection().getActionCommand();
		if (!cond3)
		{
			if(str4.equals("Deg"))
			{
				while(x>=360)
				x=x-360;
				str=""+Math_class.sin_func(Math_class.convert_deg_rad(x));
				textf.setText(""+str);
							}
			else if(str4.equals("Rad"))
			{
				while(x>=(2*Math.PI))
				x=x-Math.PI;
			str=""+Math_class.sin_func(x);
			textf.setText(str);
			}
			f.CreateFile();
			f.addTofile("Sin("+x+")="+str);
		}
		else
		{
			if(str4.equals("Deg"))
			{
				x=Double.valueOf(str).doubleValue();
				str=""+Math_class.convert_rad_deg(Math.asin(x));
				textf.setText(""+str);
				
			}
			else if(str4.equals("Rad"))
			{
				x=Double.valueOf(str).doubleValue();
				str=""+Math_class.convert_deg_rad(Math.acos(x));
				textf.setText(str);
				
			}
			str3=str;
			f.CreateFile();
			f.addTofile("aSin("+x+")= "+str);
		}
	}
	else if(e.getSource()==button[21])
	{
		pressed=true;
		double x=Double.valueOf(str). doubleValue ();
		String str4 = degree_cont.getSelection().getActionCommand();
		if (!cond3)
		{
			 if(str4.equals("Deg"))
			 {
		 		while (x>=360)
		 			x=x-360;
				str=""+Math_class.cos_func(Math_class.convert_deg_rad(x));
				textf.setText(str);
				str3=str;
				
			}
			else if(str4.equals("Rad"))
			{
			 	while(x>=(2*Math.PI))
					x=x-Math.PI;
				str=""+Math_class.cos_func(x);
				textf.setText(str);
				str3=str;
				
			}
			f.CreateFile();
			f.addTofile("Cos("+x+")="+str);
		}
		else
		{
			if(str4.equals("Deg"))
			{
				x=Double.valueOf(str).doubleValue();
				str=""+Math_class.convert_rad_deg(Math.acos(x));
				textf.setText(str);
				str3=str;
				
			}
			else if(str4.equals("Rad"))
			{
				x=Double.valueOf(str).doubleValue();
				str=""+Math_class.convert_rad_deg(Math.acos(x));
				textf.setText(str);
				str3=str;
				
			}
			f.CreateFile();
			f.addTofile("aCos("+x+") ="+str);
		}
	}
	
	else if (e.getSource()==button[0])//Power button.
	{
		if(!cond1)
		{
			cond5=true;
			textf.setBackground (Color.white);
			cond1=true;
			button[0].setLabel("OFF");
			for(int i=1;i<42;i++)
			button[i].setEnabled (true);
			button[30].setEnabled(false);
		}
		else
		{
			cond1=false;
			cond5=true;
			pressed=false;
			textf.setBackground (Color.black);
			button[0].setLabel("ON");
			for(int i=1;i<43;i++)
			button[i].setEnabled (false);
			memoryTagLabel.setText(" ");
			f.delFile();
			str="0";str1="";str2="";
			textf.setText(str);
			mem=0;
			
		}
	}
	else if(e.getSource()== button[16]) // "." Button 
	{
		if(pressed)
		{
			str="0";
			pressed=false;
		}
		if (cond5)
		{
			str=str+".";
			cond5=false;
			textf.setText(str);
		}
	}
//The implementation of the Number Buttons.
	else if ((e.getSource()==button[6]) || (e.getSource()==button[7]) || (e.getSource()==button[8]) || (e.getSource()==button[9]) || (e.getSource()==button[10]) || (e.getSource()==button[11]) || (e.getSource()==button[12]) || (e.getSource()==button[13]) || (e.getSource()==button[14]) ||(e.getSource()==button[15]) )
	{	
	if(pressed)
	{
		str="0";
		pressed=false;
	}