Why do double instance variables in java have a lower case d attached to them? Do they need to have this?
Example:
double area = 0d;
double avgDailyTemp = 26d;
etc...
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See this answer: http://stackoverflow.com/a/28353219/1057429 it talks about `long` but provides information about `double` as well – Nir Alfasi Feb 07 '15 at 22:20
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Can you reword your question, because its unclear. whats a double instance variable? double is primitive and not an object, primitives are lower cased in Java – Sleiman Jneidi Feb 07 '15 at 22:22
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@SleimanJneidi OP is asking if `d` part in `26d` is mandatory for `double`. – Pshemo Feb 07 '15 at 22:30
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I see, it doesn't need to be lower case, 26D works as well – Sleiman Jneidi Feb 07 '15 at 22:32
4 Answers
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A number literal by default is an integer. If you attempt to pass a number like ten billion into Java double it'll error since it's outside the bounds of an integer. Specifying the lowercase d explicitly defines it as a double literal instead.
Alex Popov
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1You can also add a "." at the end instead of d: `double area = 260000000000.;` – OlgaMaciaszek Feb 07 '15 at 22:49
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double a = 10000000000; // ERROR! Integer number too large
double b = 10000000000d; // OK!
MariuszS
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It is not the variable which requires the d, but the constant value declared. It is a "hint" to the compiler of the data type.
http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html
Brett Okken
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