What does Java compiler interprets by `(byte) + (char) - (int) + (long) - 1`? [duplicate]

Question

Possible Duplicate:
Weird java behavior with casts to primitive types

Why does this code in Java,

int i = (byte) + (char) - (int) + (long) - 1;
System.out.println(i);

prints 1? Why does it even compile?

Source: Java Code Geeks

Answer 1

What you are doing is combining type casts with unary operators.

So let's see:

First, you have the value -1, which you cast to the type long.

Then, you perform the unary operation +, which doesn't change the value, so you still have (long) -1.

Then, you cast it to int, so we now have int -1. Then, you use unary operator -, so we have -(-1), which is 1.

Then you cast it to char, so we have char 1. Then, you use unary operator +, so you still have 1.

Finally, the value is cast to byte, so you have byte 1. And then it is once again (implicitly) cast to int.

Answer 2

The various (<type>) parts are just casting between various types. So what happens is, reading from the right, 1 -> -1 -> (long)-1 -> (int)-1 -> -(int)-1 = 1 -> (char)1) -> (byte)1 which then gets cast to an int during the assignment. At no point does the type cast result in effective change of the value, so the entire first line is equivalent to int i = 1;.