I was trying Java9 feature JShell. I'm not able to set a float value:
jshell> float b = 3.5
Error:
| incompatible types: possible lossy conversion from double to float
| float b = 3.5;
jshell> float x =2
x ==> 2.0
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3try `3.5f` to assign value and search about `lossy conversion from double to float` – Pavneet_Singh Dec 20 '16 at 09:43
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3What's the question? Keep in mind that in Java `3.5` is a `double` literal. The equivalent `float` literal is `3.5f`. – Theodoros Chatzigiannakis Dec 20 '16 at 09:43
2 Answers
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It's Java being unduly pernickety.
The type of the literal 3.5 is a double, and you are assigning that to a float.
Since the set of possible floats is necessarily a subset of the set of possible doubles, you get a precision lost on conversion warning.
For an easy life, use 3.5f to denote a float literal.
But note that 3.5 can be represented exactly in both a double and float, so on this specific occasion, the error is hogwash.
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1In the good old days compilers would assume the programmers knew what they were doing. – Bathsheba Dec 20 '16 at 09:48
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This is the behaviour of Java (as described in the existing answer). JShell follows Java syntax and semantics exactly -- this is important so you don't develop incorrect code.
Robert Field
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