Array initialization

Hi all, not sure if this is the correct place for this question, but here goes.

I am trying to scan a binary string into an array, and then display that number back, but my problem is if I start with a 0 or multiple 0s it wont display the 0/s.

import java.util.Scanner; public class Assignment1 { public static void main(String[] args) { System.out.print("Enter an 8 bit binary number we will call A here:"); Scanner scan = new Scanner(System.in); int [] a = new int [8]; for (int i = 0; i < 8; i ++) { a[i]= scan.nextInt(); System.out.println("Your A number is " +a[i]); } } }
If i enter 01010101 it wont display that first 0, but if i enter 10101010 it is fine, any suggestions?

Thanks for the help.

[Edited : Added code tag around source]

Hi Brian,

Don't read it as a number using nextInt(); read the whole thing as a String using nextLine() .

Thanks for the quick response. Is there a reason nextInt(); wont work?

Brian

Edit: Just tried nextLine(); and get an error type missmatch, cannot convert from string to int.

not sure how a nextLine would initialize each index of the array?

The problem is... there is no formatting data in an int. It doesn't have any concept of leading zeros, etc. So, when you print out the int, you have to add the format back, which includes adding any leading zeros.

Henry

Just tried nextLine(); and get an error type missmatch, cannot convert from string to int.

I think the suggestion was to use a string instead of an int. This way, the formatting is retained, and you can print out the leading zeros. If you convert the string to an int, then you are back to your original problem, you lost any formatting data.

Henry

And BTW, you do know that in your example, your radix is 10 right? So, when 10101010 is read as an int, it is stored as 10 million, one hundred and one thousand, and ten ? And not stored as 170 (decimal equiv, I think) ?

Henry

Yes I know the number as an int is 10million plus. I don't want the number as an int I want each individual 1 or 0 to be an index of the array. I guess maybe my issue is initialing the array with the user input, maybe there is a better way?

I see what you are saying Henry, so when I use my code the first a[i] is = to the number I type in. , and doesnt actually index each individual number as a 0 or 1. now How do I overcome that issue?

public static int [] or (int [] a, int [] b) { int [] result = new int [8]; for (int i = 0; i < result.length; i++) result [i] = (a [i] == 1 || b [i] == 1) ? 1 : 0; return result; }
That is a method for displaying an or of two binary numbers.(at least i think) I am trying to read in two binary numbers each 1 byte long, and then use that method to output their or.

Brian

edit: OK I got the initialization to work if I prompt the user to add a space, using nextInt(); so 0 1 0 1 1 1 1 1 will display as that when returned. A little bit unorthodox for the user, but I cant come up with a better solution atm.


so much to learn!

Having come late to the discussion, I am a bit behind things, but your last method won't work.
You are creating a new array, then iterating through it, then returning a number, which will be the last number in the array.
A new int[] array is filled with 0s by default, so that method will always return a 0.

Go through the Integer class, and you find methods which will return their binary/octal/hexadecimal representation, but always without leading 0s.

Thanks all for the wonderful help. After much thought I figured I wouldnt be able to use an int array to do what i needed to do. At least not with my current knowledge of Java, or any programming language atm.

I have changed to this current code and for the or method it is working.

import java.util.Scanner; public class BinaryOperations { public static char [] or (char [] a, char [] b)// converts two binary strings to the or of those strings. { char [] result = new char [8]; for (int i = 0; i < 8; i++) { if (a [i] == '1' || b [i] == '1') { result [i] = '1'; } else { result [i] = '0'; } } return result; } public static void main(String[] args) { Scanner scan = new Scanner (System.in); String A1 = ""; // holds A and B input from user. String B1 = ""; System.out.print("Enter an 8 bit binary string to be called A:"); // String A1 A1 = scan.nextLine(); System.out.print("Enter an 8 bit binary string to be called B:"); // String B1 B1 = scan.nextLine(); char [] a = A1.toCharArray(); char [] b = B1.toCharArray(); System.out.println(a); System.out.println(b); System.out.println("A or B = "+ String.valueOf(BinaryOperations.or(a,b))); // displays the or as a string. } }

The converting to and from char to string then back again seems a bit cumbersome, but until I can figure out a better way this works.

I still have one issue, and that is being able to tell if a 1 or 0 is being used exclusively from the user. I am on to that bit now.

Again thanks all

Brian