Question

I understand this:

35%10 returns 5

but, why does 000000035%10 return 9?

Ruby does the same thing. I checked with irb.

Should I strip the 0s that are padding the number? What is the java function to do that?

Answer 1

When you put the leading zeros followed by octal digits (from 0 to 7), you’re creating an octal literal. And since 000000035 in octal is 29 in decimal, its remainder with 10 is 9.

UPDATE

If you have your “octal literal” in a string, simply use Integer.parseInt and you’ll get it parsed as a decimal.

assert Integer.parseInt("035") == 35;