diff between a float and a double

[maxpower1]

how can you tell a float from a double beside the ranges. For instance,

1.0 is a double
-345 is an integer(hence fits in a float var )
42e7 is a double??

2.81F is a float.
2.80f is a float.
3.14 is a double
3.14f is a float

thanks

 

[prosper]

All floating-point literals are assumed to be of type double, so 42e7 is a double.
Primitive assignment conversion:
1. A non-boolean may be converted to another non-boolean type, provided the conversion is a widening conversion.
2. A non-boolean may not converted to another non-boolean type, if the conversion would be a narrowing conversion.

Therefore
float i = 345; --> integer 345 is converted to a float

*** try this link for detailed explanation

http://java.sun.com/docs/books/jls/second_edition/html/conversions.doc.html

 

[prosper]

supplement:
char-->int-->long-->float-->double
^
I
byte-->short
The arrow --> shows the allowed widening conversion.
Reverse order need casting.
e.g.
int i = (int)123f;


Detail in primitive

http://java.about.com/library/tutorials/bltut-009d.htm

http://java.about.com/library/tutorials/bltut-009d.htm

http://java.about.com/library/tutorials/bltut-009c.htm