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Re: Need help to convert

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  Re: Need help to convert "Katak" <katak@THRWHITE.remove-dii-this> - 2011-04-27 15:43 +0000
    Re: Need help to convert "Jeff Higgins" <jeff.higgins@THRWHITE.remove-dii-this> - 2011-04-27 15:43 +0000
      Re: Need help to convert "Roedy Green" <roedy.green@THRWHITE.remove-dii-this> - 2011-04-27 15:43 +0000
        Re: Need help to convert "Katak" <katak@THRWHITE.remove-dii-this> - 2011-04-27 15:43 +0000
          Re: Need help to convert "Roedy Green" <roedy.green@THRWHITE.remove-dii-this> - 2011-04-27 15:43 +0000
      Re: Need help to convert "Katak" <katak@THRWHITE.remove-dii-this> - 2011-04-27 15:43 +0000
        Re: Need help to convert "Roedy Green" <roedy.green@THRWHITE.remove-dii-this> - 2011-04-27 15:43 +0000
          Re: Need help to convert "tar" <tar@THRWHITE.remove-dii-this> - 2011-04-27 15:43 +0000
    Re: Need help to convert "Roedy Green" <roedy.green@THRWHITE.remove-dii-this> - 2011-04-27 15:43 +0000

#3195 — Re: Need help to convert

  To: comp.lang.java.gui
I wrote these codes below in Java and theres some problems passing the
string to do the conversion. Can anyone help me out? The c++ codes are
on the first post above. Thanks.




import java.util.Scanner;


public class BinaryToDecimal {


	public static void main(String[] args) {

		   String bin;
		   int base = 10;
		   int result = 0;
		   int i;
		   double power = 0;

		   System.out.println("Enter a binary number: ");
		   Scanner input = new Scanner(System.in);
		   bin = input.nextLine();

		   for (i = bin.length()-1; i >=0; i--)
		   {




		       double cubed = java.lang.Math.pow ( 2, power);
		       result += (( bin[i] - 48)*(cubed));


		       power++;
		   }

		   System.out.print("Decimal = "+ result);
	}

}

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#3198

  To: comp.lang.java.gui

Katak wrote:

Lew suggested the String.charAt() method but,
if this is an exercize in converting
number representations by hand
  see the comment;
else
why?YourConverter:MyConverter

import java.util.Scanner;

public class YourConverter {
  public static void main(String[] args) {

    String bin;
    int result = 0;
    double power = 0;

    System.out.println("Enter a binary number: ");
    Scanner input = new Scanner(System.in);
    bin = input.nextLine();

//See Roedy Green's mindprod site for details on
//converting binary to decimal numbers

    for (int i = bin.length(); i == 0; i--) {
      double cubed = Math.pow(2, power);
      result += ((bin.charAt(i) - 48) * (cubed));
      power++;
    }
    System.out.print("Decimal = " + result);
  }

}

Enter a binary number:
1101
Decimal = 0


public class MyConverter {

  public static void main(String[] args) {

    String hexString = "4341464542414245";
    Long dec = Long.valueOf(hexString, 16);
    String bin = Long.toBinaryString(dec);

    System.out.println(dec  + " : " + hexString);
    System.out.println(bin);

  }
}

4846231937305625157 :
4341464542414245
1000011010000010100011001
00010101000010010000010100001001000101

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#3200

  To: comp.lang.java.gui
On Sat, 23 Feb 2008 16:17:52 -0500, "Jeff Higgins"
<oohiggins@yahoo.com> wrote, quoted or indirectly quoted someone who
said :

> double cubed = Math.pow(2, power);

for cubed I would use  double cubed = x * x * x;

Math.pow works by taking logs and exponentials, each of which is
computed with a whacking huge polynomial approximation. With the
arithmetic method, you don't lose precision on doubles that happen to
be perfect  ints.

--

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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#3202

  To: comp.lang.java.gui
On Feb 24, 6:08 am, Roedy Green <see_webs...@mindprod.com.invalid>
wrote:
> On Sat, 23 Feb 2008 16:17:52 -0500, "Jeff Higgins"
> <oohigg...@yahoo.com> wrote, quoted or indirectly quoted someone who
> said :
>
> > double cubed = Math.pow(2, power);
>
> for cubed I would use  double cubed = x * x * x;
>
> Math.pow works by taking logs and exponentials, each of which is
> computed with a whacking huge polynomial approximation. With the
> arithmetic method, you don't lose precision on doubles that happen to
> be perfect  ints.
>
> --
>
> Roedy Green Canadian Mind Products
> The Java Glossaryhttp://mindprod.com

Sorry. I think it was meant to be exponent since I was doing decimal =
binary * 2^1 , decimal = binary * 2*2, etc.  Named it wrongly.

Thanks a lot.

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#3205

  To: comp.lang.java.gui
On Sat, 23 Feb 2008 20:42:18 -0800 (PST), Katak
<vampireex@hotmail.com> wrote, quoted or indirectly quoted someone who
said :

>Sorry. I think it was meant to be exponent since I was doing decimal =
>binary * 2^1 , decimal = binary * 2*2, etc.  Named it wrongly.

In that case you can often use a loop to incrementally create a power,
especially if you need to intermediate values.

pow *= base;

You can create powers of two with left shifts.  e.g.

1 << 3 == 8
--

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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#3204

  To: comp.lang.java.gui
On Feb 24, 5:17 am, "Jeff Higgins" <oohigg...@yahoo.com> wrote:
> Katak wrote:
>
> Lew suggested the String.charAt() method but,
> if this is an exercize in converting
> number representations by hand
>   see the comment;
> else
> why?YourConverter:MyConverter
>
> import java.util.Scanner;
>
> public class YourConverter {
>   public static void main(String[] args) {
>
>     String bin;
>     int result = 0;
>     double power = 0;
>
>     System.out.println("Enter a binary number: ");
>     Scanner input = new Scanner(System.in);
>     bin = input.nextLine();
>
> //See Roedy Green's mindprod site for details on
> //converting binary to decimal numbers
>
>     for (int i = bin.length(); i == 0; i--) {
>       double cubed = Math.pow(2, power);
>       result += ((bin.charAt(i) - 48) * (cubed));
>       power++;
>     }
>     System.out.print("Decimal = " + result);
>   }
>
> }
>
> Enter a binary number:
> 1101
> Decimal = 0
>
> public class MyConverter {
>
>   public static void main(String[] args) {
>
>     String hexString = "4341464542414245";
>     Long dec = Long.valueOf(hexString, 16);
>     String bin = Long.toBinaryString(dec);
>
>     System.out.println(dec  + " : " + hexString);
>     System.out.println(bin);
>
>   }
>
> }
>
> 4846231937305625157 :
> 4341464542414245
> 1000011010000010100011001
> 00010101000010010000010100001001000101


Thanks. I've fixed a lil bit of it and it works well now. Updated
codings are as below.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;


public class BinaryToDecimal {

   private static BufferedReader stdin= new BufferedReader(new
InputStreamReader(System.in));

   public static void main(String[]args) throws IOException{

      int result = 0;
	  double power = 0;
	  System.out.println("Enter a binary number: ");
	  String bin = stdin.readLine();
	  System.out.println("Binary = " + bin);

      for (int i = bin.length()-1; i >= 0; i--) {
         double exponent = Math.pow(2, power);
         result += ((bin.charAt(i) - 48) * (exponent));
         power++;
      }

      System.out.print("Decimal = " + result);

   }
}

//Now for the gui part >_<

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#3206

  To: comp.lang.java.gui
On Sat, 23 Feb 2008 20:46:10 -0800 (PST), Katak
<vampireex@hotmail.com> wrote, quoted or indirectly quoted someone who
said :

>   double exponent = Math.pow(2, power);
>         result += ((bin.charAt(i) - 48) * (exponent));
>         power++;

Shift would be more accurate and much much faster.

power = 1;
...
power <<= 1;

or even better just shift (bin.charAt(i) - '0') directly by i.

see http://mindprod.com/jgloss/shift.html
http://mindprod.com/jgloss/binary.html
http://mindprod.com/jgloss/precedence.html
http://mindprod.com/jgloss/bit.html
http://mindprod.com/jgloss/masking.html
--

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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#3219

  To: comp.lang.java.gui
Roedy Green <see_website@mindprod.com.invalid> writes:

> On Sat, 23 Feb 2008 20:46:10 -0800 (PST), Katak
> <vampireex@hotmail.com> wrote, quoted or indirectly quoted someone who
> said :
> 
> >   double exponent = Math.pow(2, power);
> >         result += ((bin.charAt(i) - 48) * (exponent));
> 
> or even better just shift (bin.charAt(i) - '0') directly by i.

or even better:

   shift  Character.digit(bin.charAt(i),2)

-- 
Thomas A. Russ,  USC/Information Sciences Institute

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#3199

  To: comp.lang.java.gui
On Sat, 23 Feb 2008 11:06:36 -0800 (PST), Katak
<vampireex@hotmail.com> wrote, quoted or indirectly quoted someone who
said :

>I wrote these codes below in Java and theres some problems passing the
>string to do the conversion.

for all your conversion needs, see
http://mindprod.com/applet/converter.html

It will show you for example, how to convert your double to a String
you could feed to a JTextField.
--

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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