否定整数会产生意外结果

Question

I am unable to understand how the following code gives -12. Please help me.

int a=11;    
int result=~a;    
System.out.println(result);    

I thought it will give 4. but yes I saw a preceding zero.
I guess it has got something to do with 2's complement but cant makes out how.

Answer 1

11 's binary representation is 00000000000000000000000000001011 .

The negation of that number is 11111111111111111111111111110100 .

That's the 2's complement representation of -12 .