Please someone help me with this calculator...due tomorrow..

[jvpk4]

This is my code.. everything is working fine.. i just need the code to this calculator can ADD subtract more than 2 digits.. and this is all new to me. and this assignment is due tomorrow.. plzzz help.. i would appreciate it very much...:--

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

//This is the accumulator program that adds and subtracts numbers
//The input comes through the keypad
//This program is written by ME

public class Adding_Machine extends JApplet
{
	JTextField jtfInput = new JTextField(50);

	Font f1 = new Font("Forte",Font.BOLD,20);

	JButton jbtClear = new JButton("Clear");
	JButton jbt7 = new JButton("7");
	JButton jbt8 = new JButton("8");
	JButton jbt9 = new JButton("9");
	JButton jbt4 = new JButton("4");
	JButton jbt5 = new JButton("5");
	JButton jbt6 = new JButton("6");
	JButton jbt1 = new JButton("1");
	JButton jbt2 = new JButton("2");
	JButton jbt3 = new JButton("3");
	JButton jbtMinus = new JButton("-");
	JButton jbt0 = new JButton("0");
	JButton jbtPlus = new JButton("+");

	//implements constructor. creates the buttons textfield and panel
	public void init()
	{
		JPanel p1 = new JPanel();
		p1.setBackground(Color.GREEN);
		p1.setLayout(new GridLayout(4,3,5,5));
		p1.add(jbt7);
		p1.add(jbt8);
		p1.add(jbt9);
		p1.add(jbt4);
		p1.add(jbt5);
		p1.add(jbt6);
		p1.add(jbt1);
		p1.add(jbt2);
		p1.add(jbt3);
		p1.add(jbtMinus);
		p1.add(jbt0);
		p1.add(jbtPlus);

		jbt9.setFont(f1);
		jbt9.setForeground(Color.BLUE);
		jbt8.setFont(f1);
		jbt8.setForeground(Color.BLUE);
		jbt7.setFont(f1);
		jbt7.setForeground(Color.BLUE);
		jbt6.setFont(f1);
		jbt6.setForeground(Color.BLUE);
		jbt5.setFont(f1);
		jbt5.setForeground(Color.BLUE);
		jbt4.setFont(f1);
		jbt4.setForeground(Color.BLUE);
		jbt3.setFont(f1);
		jbt3.setForeground(Color.BLUE);
		jbt2.setFont(f1);
		jbt2.setForeground(Color.BLUE);
		jbt1.setFont(f1);
		jbt1.setForeground(Color.BLUE);
		jbt0.setFont(f1);
		jbt0.setForeground(Color.BLUE);
		jbtMinus.setForeground(Color.RED);
		jbtMinus.setFont(f1);
		jbtPlus.setForeground(Color.RED);
		jbtPlus.setFont(f1);
		jbtClear.setForeground(Color.RED);
		jbtClear.setFont(f1);

		getContentPane().add(jtfInput, BorderLayout.NORTH);
		getContentPane().add(p1, BorderLayout.CENTER);
		getContentPane().add(jbtClear, BorderLayout.SOUTH);
	}

	//main driver that sets off parameters of the frame
	public static void main(String [] args)
	{
		Adding_Machine applet = new Adding_Machine();
		applet.init();
		JFrame frame = new JFrame();
		frame.add(applet.getContentPane());
		frame.setTitle("Adding Machine");
		frame.setLocation(300,200);
		frame.setSize(300,400);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}
	}

[Eranga]

Please use code tags when you are posting again in the forum. Unformated codes are really hard to read. If you don't know how to do it, check my forum signature.

[Eranga]

Regarding your question, where did you do the calculation part. I cannot see that you've done related to that, only the UI.

[pbrockway2]

I might be missing something here but the purpose of an assignment is to give you the opportunity to learn something. It's like going to the gym: the point is to get healthy.

Other people could go to the gym for you. But they would get healthy, and you would miss out.

I wouldn't want you to miss out so write your own code and, if you encounter a problem, post a question about that.

[Eranga]

I agreed with you pbrockway2. And also this is an assignment, so OP must show his/her effort. I believe that this code is written by him, but then why he's not even give a try on the rest.

[jvpk4]

yes u guys are right.. but i dont know how can i add

the addition or subtraction code.. thats where i am really confused.. i dont know how and where to add the addition and subtraction code..

[Fubarable]

yes u guys are right.. but i dont know how can i add

the addition or subtraction code.. thats where i am really confused.. i dont know how and where to add the addition and subtraction code..

You've got a bunch of JButtons, so adding action listeners to the JButtons would seem like a great place to start. A method that does this is the addActionListener(ActionListener al) method of JButton (actually AbstractButton which JButton extends). To learn how to do this, go to the Sun Swing button tutorial: How to use Buttons

Luck!

[jvpk4]

thanks, it making sense... kinda.. lol

[Webuser]

Your project doesn't contain a BL so I think you have to develope it first or to find a code and add it for your GUI :)
I recommend reading this Writing Calculator program in Swing
and this Java Swing Calculator Source Code

[alacn]

you should delare your JButtons etc as an array, and then u can manipulate then all with a loop. makes code alot more cleaner

[Eranga]

yes u guys are right.. but i dont know how can i add

the addition or subtraction code.. thats where i am really confused.. i dont know how and where to add the addition and subtraction code..

Okay, to start up please write down your logic, that's the way you are going to done this. Then try to identify where you should implement it. Fubarable says something about action listeners, where your control events invoke.

Did you do anything on that?

[JvlShz]

1) To create a calculator, you need some kind of parse tree. I would strongly recommend an Abstract Syntax Tree.

2) Recursion can be used to create a tree, by looping operators in order of precedence (eg: addition, subtraction, multiplication then division)

3) When you have built your syntax tree, you can start from the root node, and begin a post-tree-recursion to find the lowest node. From there, you can begin using the operators. For example:

4 + 1 becomes

       +
     /   \
    /     \
   4      1

from there, we can use the plus to know that 4 adds with 1.

This can be extended to create very very complex structures, involving lots more mathematical operators, but this is enough to get you started.

HTH,

Jvl

[Eranga]

I'm sure that use of abstract syntax tree is the most easiest as well as most suitable way to workout this application. But I don't know how much easier to understand and implement it within our OPs' code. He's still struggling with the basic implementation.

[Lil_Aziz1]

1) To create a calculator, you need some kind of parse tree. I would strongly recommend an Abstract Syntax Tree.

2) Recursion can be used to create a tree, by looping operators in order of precedence (eg: addition, subtraction, multiplication then division)

3) When you have built your syntax tree, you can start from the root node, and begin a post-tree-recursion to find the lowest node. From there, you can begin using the operators. For example:

4 + 1 becomes

       +
     /   \
    /     \
   4      1

from there, we can use the plus to know that 4 adds with 1.

This can be extended to create very very complex structures, involving lots more mathematical operators, but this is enough to get you started.

HTH,

Jvl

Inorder tree traversal, not postorder.

[Eranga]

Not interest at all, the idea is how far our OP could implement it. I don't think at the moment it's not suitable to use, isn't it?

[Lil_Aziz1]

Oh. Yea that's reasonable. Sorry about that.

[Eranga]

Oh. Yea that's reasonable. Sorry about that.

Hey lol. I'm not saying that what you've said is wrong. Honestly I've never recognize that there is any error, until you pointed it here.

What I want to point is that looking at the OPs' code I'm sure that he/she relly confuse with this. ;)