Came across the following expression on Java and I have no idea what "1d" means (r is an integer). There are also options for longs, doubles... What are they and what are they used for?
double y = r / (Integer.MAX_VALUE + 1d);
Thanks!
Asked
Active
Viewed 2.4k times
14
-
5It's a `double` literal. – August Dec 08 '14 at 22:46
-
... and for avoiding integer division. – Alexis C. Dec 08 '14 at 22:46
-
Equivalent to casting then? – aralar Dec 08 '14 at 22:47
-
1Kind of shorthand for 1.0, and it implies double-precision. `1f` would do the same thing only it would be single-precision. – Andon M. Coleman Dec 08 '14 at 22:47
-
No. It will not get casted, it originally creates a double value, just like `1.0`. – Gábor Bakos Dec 08 '14 at 22:47
-
Not casting. This is a literal value. By default Java interpret a number like 1 as an int. If you intend a floating point value like 1.0 instead then you add the suffix d t indicate that the literal value is to be interpreted as a double. – Vincent Ramdhanie Dec 08 '14 at 22:49
-
Why do this vs. multiplying one of the integers (like `r` above) by 1.0? – aralar Dec 08 '14 at 22:49
1 Answers
39
Sufix d after number means double, sufix f means float.
You can express double literal in eight ways: 1.0, 1d, 1D, 1.0d, 1.0D, 1., 1.d, 1.D and not truly double literal: (double)1. In the last example 1 is the literal, it is an int but then I cast it to double.
In your expression: double y = r / (Integer.MAX_VALUE + 1d); parentheses increase priority of expression so the (Integer.MAX_VALUE + 1d) will be evaluated first and because this is intValue + doubleValue the outcome will be of type double so r / (Integer.MAX_VALUE + 1d) will be also a double.
Yoda
- 17,363
- 67
- 204
- 344