1 / 2 = 0

Question

I wonder if this is a bug or just an unfriendly behaviour of Java:
System.out.println("1) 1/2 : "+ (1/2));
double d = 1/2;
System.out.println("2) 1/2 : "+d);The results are "0" and "0.0". Whereas
double dd = 1.0/2;
System.out.println("3) 1.0/2 : "+dd);
System.out.println("4) (double) 1/2 : "+ ((double) 1/2));prints the correct "0.5" result. I also debugged this code and saw that the internal state of "d" is "0.0" - before concatenating with the string. It seems that Java is automatically "casting" numeric results to int if not explicitaly specified differently? I doubt that this is a good default behaviour.

Answer 1

It is C heritage.
If all operands are int (or byte, char, short), then a formula will have the type int.
byte b='\0';
b + 1 ; // it is of type int Thus dividing two integers will yield an int and the division will be integer division.
It is OK once you got accustomed to it in the C-derived languages (c, C++, java).