Question

I have a long variable in java and am converting it to a binary string, like

long var = 24;
Long.toBinaryString(val);

Now this prints only 7 bits, but I need to display all the 64 bits, i.e. all the leading zeros also, how can I achieve this?

The reason is I need to iterate through each bit and perform an operation according to the status, is there a better way to do it?

Answer 1

If you want to iterate through the bits, you might be better off testing each bit without converting it to a string:

if ((val & (1L << bitPosition)) != 0)
    // etc

But, if you truly want a binary string, this is the easiest way to left-pad it with zeros:

string padding = "0000000000000000000000000000000000000000000000000000000000000000";
string result = padding + Long.toBinaryString(val);
result = result.substring(result.length() - 64, result.length());  // take the right-most 64 digits