Binary addition,subtraction and modulus...plz help urgent

Question

plz help me on this query...
i need to pass two 512 bit number as string,then convert them to binary and
then perform binary addition,subtraction,modulus operations on those two numbers.finally convert result to integer.
i designed a code which doesnt work correct.it is:
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package bytearrayopeations;
import java.math.BigInteger;   
* @author sheetalb
public class binaryadding {
    public static void main(String[] args) {
        BigInteger a = new BigInteger("123456");
        BigInteger b = new BigInteger("5121");
        String bb1 = a.toString(2);
        String bb2 = b.toString(2);
        String ss1 = null;
        String ss2 = null;
        String result = "";
        String carry="0";
        System.out.println("first value=" +bb1);
        System.out.println("second value=" +bb2);
        int k=bb1.length();
        int h=bb2.length();
        System.out.println("length 1="+ k);
        System.out.println("length 2=" +h);
        int p=h-k;
        //System.out.println("difference=" +p);
        int q=k-h;
        //System.out.println("difference 2=" +q);
        if(h==k)
       else if(h>k)
            for(int i=0;i<p;i++)
                bb1="0"+bb1;
            System.out.println("new value of first=" +bb1);   
    else if(h<k)
        for(int i=0;i<q;i++)
            bb2="0"+bb2;
        System.out.println("new value of second=" +bb2);
        StringBuffer sb1=new StringBuffer(bb1);
     StringBuffer sb2=new StringBuffer(bb2);
        bb1=sb1.reverse().toString();
     bb2=sb2.reverse().toString();
        //System.out.println("rev. buffer1=" +bb1);
        //System.out.println("rev. buffer2=" +bb2);
        for(int i=0;i<bb1.length();i++)
            ss1=bb1.substring(i,i+1);
            ss2=bb2.substring(i,i+1);
          System.out.println("value1=" + ss1 + "    " + "value2=" + ss2);
          if (ss1.equals("0") && ss2.equals("0")) 
             if (carry.equals("0")) 
                 result+="0";
                    else
                        result+="1";
           else if (ss1.equals("1") && ss2.equals("1"))
            if (carry.equals("0")) 
                result+="0";
          carry="1";
          else
               result+="1";
               carry="1";
    else if (ss1.equals("0") && ss2.equals("1"))
                 if (carry.equals("0")) 
                     result+="1";
               carry="0";
                    else
                      result+="0";
                                carry="1";
           else if (ss1.equals("1") && ss2.equals("0"))
                 if (carry.equals("0")) 
                    result+="1";
                    carry="0";
               else
                            result+="0";
                            carry="1";
       System.out.println("sum=" +result + "         " + "carry" + carry);
                    result+=carry;
                    StringBuffer sb3=new StringBuffer(result);
                    result=sb3.reverse().toString();
                System.out.println("result is " +result); 
              System.out.println("Binary = "+ result + ", Decimal = "+Integer.parseInt(result,2));
}plz provide me or email me if possible java coding for all three operations as soon.
[email protected]

Answer 1

One thread is enough. Continue here:[http://forums.sun.com/thread.jspa?threadID=5373720&messageID=10643157#10643157]