How do I print the binary representation of the first character in a string

Question

i want to retrieve the binary values of the data in the file. so i have written the following the code:

while ((fileData = br.readLine()) != null) {
  byte b[] = fileData.getBytes("UTF-8");
  BigInteger bi = new BigInteger(b);
  String s = bi.toString(2);
  System.out.println("Original message in binary: " + s);
  System.out.println("Original message length: " + s.length());
}

output:

abca (this is the data in a text file)
Original message in binary: <here>1100001011000100110001101100001
Original message length: 31

Everything is fine but while i am printing the data in binary format i am not able to print the first bit ( <here> ) can anyone help me?

Answer 1

For first character:

s.charAt(0);

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EDIT: If you want to print the binary representation of first byte then try this:

    String str = Integer.toBinaryString("abca".getBytes("UTF-8")[0]);
    System.out.println(str);

EDIT 2: Try this for leading zeroes.

static String addLeadingZeroes(String s) {
    int zeroes = s.length() % 8;
    byte[] bzero = new byte[8 - zeroes];
    Arrays.fill(bzero, (byte)0x30);
    return new StringBuilder(new String(bzero)).append(s).toString();
}

and call as

System.out.println("Original message in binary: "+ addLeadingZeroes(s));

Answer 2

I assume what you're saying is that when the first binary digit is a "0", that it is not displayed. If you want to insure that you're displaying a full 32 binary digits, you can use the following code.

public static final THIRTYTWO_ZEROS = "00000000000000000000000000000000";

String s = bi.toString(2);
s = THIRTYTWO_ZEROS.substring(s.length) + s;

This has the effect of padding your string with preceding "0" characters to a length of 32 characters.