array of char

[sinisab]

Hi,
I have a problem with array. Inputs are size of binary number and integer. I need to create char array from that integer with leading zeroes (I need those 0`s later for a logical operations). Problem is that I can not get those 0`s as a result. Can anyone help me, please?

public class adder {
	
	static int size;
	
	public static void main (String[]args){
	
	Scanner input = new Scanner (System.in);
	System.out.println("size of binary number");
	size = input.nextInt();
	System.out.println("enter number?");
	int firstNumber = input.nextInt();
	String binaryNumber = Integer.toBinaryString(firstNumer);
	addZeroes (binaryNumber);
	char[] firstList = new char [size];
	firstList = binaryNumber.toCharArray();
	System.out.println(firstList);
	}
	
	public static String addZeroes(String a) {
		int i;
		i = a.length();
		if (i == size)
			return a;
		else
		{
			int j = size - i;
			for (int k=0; k<j; k++)
			{
				a = "0" + a;				
			}
			return a;		
		}
	}

}

[Supamagier]

main {
binaryNumber = addZeroes(binaryNumber);
}


public static String addZeroes(String a) {
		while (a.length() != size)
                    a = "0"+a;
                return a;		
	}

should work.

EDIT: Btw, printing an array will just show you the name of the object. You should loop through the array and print each element to print the contents.

[Fubarable]

Remember that Strings are immutable. So this

addZeroes(binaryNumber);

creates a String with leading zeros but then discards the String.

You want to get that String returned and use it. i.e.,

      //!! addZeroes(binaryNumber);
      //!! char[] firstList = new char[size];
      //!! firstList = binaryNumber.toCharArray();
      String addedZeros = addZeroes(binaryNumber);  // get the result of the method
      char[] firstList = addedZeros.toCharArray();   // and use it here

Also, note that I added code tags to your original post to help make it readable. Please see my signature to learn how to do this yourself.

Oh, and welcome to the forum!

[sinisab]

Fubarable,
thank you!
Just, in last line char[] is not needed (duplicate local variable).
Thank you again!

[Fubarable]

Fubarable,
thank you!

You're quite welcome.

Just, in last line char[] is not needed (duplicate local variable).

That's because in my code I declared the char array variable on the same line that I created it (via String#toCharArray() method).

[Supamagier]

I feel ignored xD

Please mark the thread as SOLVED. :)

[sinisab]

Supamagier,
Sorry! Thank you, also. Your method AddZeros is efficient than mine, so I will use that.
I will mark this as solved, just to see how to do that. I`m new in forum and Java also. Forgive me.

[Fubarable]

Yep, super was first with the good idea and should get credit. Thank you, sinisab for correcting this.

[[RaIdEn]]

lol supa...I too feel ignored .:( ...I want a bear hug Fuda.;)

[AndreB]

if you only need a string representation then this is your friend

		NumberFormat nf = NumberFormat.getInstance();
		nf.setMinimumIntegerDigits(11);
		nf.setGroupingUsed(false);
		System.out.println(nf.format(1234));