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 02052014, 09:57 PM #1Member
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Adding and Subtracting positive or negative two numbers of any length with strings
You are to design a Java application to carry out additions and subtractions for numbers of any length. A number is represented as an object which includes a sign and two strings for the whole and decimal parts of the number. And, the operations must be done by adding or subtracting characters directly. You are not allowed to convert these strings to numbers before the operation.
The program must use a "Number" class which includes at least the following methods:
Number ( );
Number (double n);
Number add (Number RHS);
Number subtract (Number RHS);
String toString ( );
The below code is what our teacher gave us to start with, but it needs to add and subtract positive or negative numbers of any length. This code only adds positive numbers. Need to write code for subtraction . help
Java Code:import java.util.Scanner; public class Number{ private String whole; private String decimal; private String sign; public static void main (String[] args){ System.out.println("Enter two numbers"); Scanner keyboard = new Scanner(System.in); Double firstNumber = keyboard.nextDouble(); Double secondNumber = keyboard.nextDouble(); Number x = new Number (firstNumber); Number y = new Number (secondNumber); Number sum = x.add(y); System.out.println ("x = " + x); System.out.println ("y = " + y); System.out.println("x + y = " + sum); Number subtract = x.Subtract(y); System.out.println("x  y = " + subtract); } public Number(){ whole = "0"; decimal = "0"; sign = "+"; } public Number (double n){ whole = "0"; decimal = "0"; sign = "+"; String temp = new Double(n).toString(); if (temp.charAt(0) == ''){ sign = ""; temp = temp.substring(1); } int pos = temp.indexOf("."); if (pos == 1) whole = temp; else { whole = temp.substring (0,pos); decimal = temp.substring (pos+1); } } public Number add (Number RHS){ this.alignWhole (RHS); this.alignDecimal (RHS); return this.addNum (RHS); } private void alignWhole (Number RHS){ int firstWholeL = this.whole.length(); int secondWholeL = RHS.whole.length(); int dif = firstWholeL  secondWholeL; if (dif > 0){ for (int i = 1; i <= dif; i++) RHS.whole = "0" + RHS.whole; } else if (dif < 0) { dif = Math.abs (dif); for (int i = 1; i <= dif; i++) this.whole = "0" + this.whole; } } private void alignDecimal (Number RHS) { int firstDecimalL = this.decimal.length ( ); int secondDecimalL = RHS.decimal.length ( ); int dif = firstDecimalL  secondDecimalL; if (dif > 0) { for (int i = 1; i <= dif; i++) RHS.decimal = RHS.decimal + "0"; } else if (dif < 0) { dif = Math.abs (dif); for (int i = 1; i <= dif; i++) this.decimal = this.decimal + "0"; } } private Number addNum (Number RHS){ Number sum = new Number(); sum.decimal = ""; int carry = 0; int decimalL = this.decimal.length(); for (int i = decimalL 1; i >= 0; i) { char firstC = this.decimal.charAt(i); char secondC = RHS.decimal.charAt(i); int sumX = (firstC  48) + (secondC  48) + carry; char sumC = (char)((sumX % 10) + 48); carry = sumX / 10; sum.decimal = sumC + sum.decimal; } sum.whole = ""; int wholeL = this.whole.length(); for (int i = wholeL 1; i >= 0; i) { char firstC = this.whole.charAt (i); char secondC = RHS.whole.charAt (i); int sumX = (firstC  48) + (secondC  48) + carry; char sumC = (char)((sumX % 10) + 48); carry = sumX / 10; sum.whole = sumC + sum.whole; } if (carry != 0) sum.whole = "1" + sum.whole; return sum; } public String toString() { return sign + whole + "." + decimal; } }
Last edited by beginner234; 02052014 at 09:59 PM.
 02052014, 10:14 PM #2Just a guy
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Re: Adding and Subtracting positive or negative two numbers of any length with string
That's not how it works. You need to make a start, not just dump the homework and ask for help.
You will probably first want to write out on a piece of paper what your code needs to do. It will probably help to use the addition code that is given to you as a source of inspiration. Which probably means that you first need to figure out how that code works and why it does what it does."Syntactic sugar causes cancer of the semicolon."  Alan Perlis
 02052014, 11:08 PM #3
Re: Adding and Subtracting positive or negative two numbers of any length with string
If you don't understand my response, don't ignore it, ask a question.
 02052014, 11:55 PM #4
Re: Adding and Subtracting positive or negative two numbers of any length with string
To the OP: when the first words of your post are "You are to design a Java application..." I *IMMEDIATELY* stop reading and stop caring. The "HOMEWORK ALERT" is triggered and it stops me from reading any further. If you can't handle the CS/Programming/Java class, then by all means drop it, but don't let us do your homework. At least pay me for it. Oh no, I won't do that either. I smell hamburgers and fries....
"It's not fixed until you stop calling the problem weird and you understand what was wrong."  gimbal2™ © 2013
 02062014, 09:39 AM #5Just a guy
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 02062014, 09:58 AM #6
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 02062014, 11:08 AM #7Just a guy
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Re: Adding and Subtracting positive or negative two numbers of any length with string
Chili Con Carne with extra chili (or Chili Con Pollo, equally tasty). That will clear your nose up right away, guaranteed.
"Syntactic sugar causes cancer of the semicolon."  Alan Perlis
 02062014, 08:41 PM #8
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 02072014, 09:13 AM #9Just a guy
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Re: Adding and Subtracting positive or negative two numbers of any length with string
*sings* Mr booze, mr booze. Mister b double o z e that sure spells boohoooooooooze...
Its Friday!"Syntactic sugar causes cancer of the semicolon."  Alan Perlis
 02072014, 09:34 AM #10
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Re: Adding and Subtracting positive or negative two numbers of any length with string
cenosillicaphobia: the fear for an empty beer glass
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