How to convert a long to a fixed-length 16-bit binary string?

Question

Hi i want to convert a long integer to binary but the problem is i want a fixed 16 bit binary result after conversion like if i convert 2 to 16 bit binary it should give me

Answer 1

Most likely what you want is Integer.toBinaryString(), combined with something to ensure that you get exactly 16 places:

int val = 2;
String bin = Integer.toBinaryString(0x10000 | val).substring(1);

The idea here is to get the zero padding by putting a 1 in the 17th place of your value, and then use String.substring() to chop off the leading 1 this creates, thus always giving you exactly 16 binary digits. (This works, of course, only when you are certain that the input is a 16-bit number.)

Answer 2

I'm presuming that you want a String output of fixed length (16). Here's what the code would look like:

String binarized = Integer.toBinaryString(i);
int len = binarized.length();
String sixteenZeroes = "00000000000000000";
if (len < 16)
  binarized = sixteenZeroes.subString(0, 16-len).concat(binarized);
else
  binarized = binarized.subString(len - 16);
return binarized;

Warning: I didn't compile or run it, so make sure no bug is there :)