Java: sum of two integers being printed as concatenation of the two

Question

Consider this code:

int x = 17;
int y = 013;
System.out.println(\"x+y = \" + x + y);

When I run this code I get the output 1711. Can anybod

Answer 1

Numbers prefixed with 0 are octal. 13 Octal is 11 decimal.

The x + y call treats both paramters as strings, so you are combining the string "17" and "11".

Answer 2

everyone mentioned 0 makes the number octal.
I just want to add that 0x makes it hexadecimal

Answer 3

013 is ocatal ... convert it to decimal and you will get 11. Have a look here for an explanation of the octal system.

Answer 4

I would just add to Reed's explanation that 013 is interpreted as Octal 13, which is decimal 11.