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Thread: I need help

  1. #1
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    Default I need help

    hey,
    I`m new in this forum and this is my first experiance in such forums....
    Something about me: my name is Marijana, I`am a 19 years old and i am study...and don`t know what to say another...
    Now I need help from you.My code below is for multipling two binary number in IEEE 735 standard and I have this
    package proekt2;
     
    public class ArrayUtils{
     
        static String[] lookupTable = {
            "0+0+0=00",
            "0+0+1=01",
            "0+1+0=01",
            "0+1+1=10",
            "1+0+0=01",
            "1+0+1=10",
            "1+1+0=10",
            "1+1+1=11",
        };
       public  static String lookup(char b1, char b2, char c) {
            String formula = String.format("%c+%c+%c=", b1, b2, c);
            for (String s : lookupTable) {
     
                if (s.startsWith(formula)) {
                    return s.substring(s.indexOf("=") + 1);
     
                }
            }
            throw new IllegalArgumentException();
     
        }
       public static String zeroPad(String s, int length) {
            while (s.length() < length) {
                s = "0" + s;
            }
            return s;
        }
        public static String add(String s1, String s2) {
            int length = Math.max(s1.length(), s2.length());
            s1 = zeroPad(s1, length);
            s2 = zeroPad(s2, length);
            String result = "";
            char carry = '0';
            for (int i = length - 1; i >= 0; i--) {
                String columnResult = lookup(s1.charAt(i), s2.charAt(i), carry);
                result = columnResult.charAt(1) + result;
                carry = columnResult.charAt(0);
            }
            if (carry == '1') {
                result = carry + result;
            }
            return result;
        }
     
     public static String multiply(String s1, String s2) {
        String result = "";
        String zeroSuffix = "";
        for (int i = s2.length() - 1; i >= 0; i--) {
            if (s2.charAt(i) == '1') {
                result = add(result, s1 + zeroSuffix);
            }
            zeroSuffix += "0";
        }
        return result;}
    }

    i call in another class with in this way
    String proiz=null;
      int pBrojac=0;
        System.out.print(ArrayUtils.add(binaren, binaren2));
        System.out.println();
        System.out.print(ArrayUtils.zeroPad(proiz, pBrojac));
        System.out.println();
        System.out.print(ArrayUtils.multiply(binaren, binaren2));


    and the mistake is this

    Exception in thread "main" java.lang.IllegalArgumentException
    at proekt2.ArrayUtils.lookup(ArrayUtils.java:24)
    at proekt2.ArrayUtils.add(ArrayUtils.java:40)
    at proekt2.Kraj.main(Kraj.java:188)
    Java Result: 1

  2. #2
    mmm.. coffee JavaPF's Avatar
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    Default Re: I need help

    Hello Marijana.
    Welcome to the Java Programming Forums.

    Don't forget you need to have the binaren and binaren2 variables..

    		String proiz = null;
    		int pBrojac = 0;
     
    		String binaren = "binaren";
    		String binaren2 = "binaren2";
     
    		System.out.print(ArrayUtils.add(binaren, binaren2));
    		System.out.println();
    		System.out.print(ArrayUtils.zeroPad(proiz, pBrojac));
    		System.out.println();
    		System.out.print(ArrayUtils.multiply(binaren, binaren2));

    Looking at your code, you are throwing the IllegalArgumentException() which would suggest there is a problem here:

       public  static String lookup(char b1, char b2, char c) {
            String formula = String.format("%c+%c+%c=", b1, b2, c);
            for (String s : lookupTable) {
     
                if (s.startsWith(formula)) {
                    return s.substring(s.indexOf("=") + 1);
     
                }
            }
            throw new IllegalArgumentException();
     
        }
    Please use [highlight=Java] code [/highlight] tags when posting your code.
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  3. #3
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    Default Re: I need help

    yes, i know that there is the problem but u don`t know how to repair it