Why “010” equals 8?

Question

My simple question is why:

System.out.println(010|4);

prints \"12\"? I understand bitwise OR operator but why \"010\" equals 8? It\'s defin

Answer 1

As everybody mentioned here that 010 is an Octal Integer literal . The leading 0 specifies that it is an octal representation . Actual value will be :

1*8^1 + 0*8^0 = 8(decimal) = 1000(binary-only last 4 digits)

Now coming back to the SOP :

System.out.println(010|4);

Applying Bitwise OR on 010 and 4(considering only the last 4 digits) =>

1000|0100

= 1100

= 1*2^3 + 1*2^2 + 0*2^1 + 0*2^0

= 8 + 4 + 0 + 0

= 12(decimal)