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static variables

 
Greenhorn
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how come Double.NaN == Double.NaN returns false. My guess is that they should return true because the are the same static class variable and they have the same value. Confused.
 
Ranch Hand
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Hi,
From JLS 4.2.3


NaN is unordered, so the numerical comparison operators <, <=, >, and >= return false if either or both operands are NaN (�15.20.1). The equality operator == returns false if either operand is NaN, and the inequality operator != returns true if either operand is NaN (�15.21.1). In particular, x!=x is true if and only if x is NaN, and (x<y) == !(x>=y) will be false if x or y is NaN.


Hope this helps,
Vanitha.
 
Ryan Deiter
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What do you mean when you say NaN is unordered. I don't understand what you mean when you say unordered.
 
Sheriff
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Hello,
Take a look at the section of the The Java Language Specification that Vanitha quoted from. It describes what it means by ordered:


Except for NaN, floating-point values are ordered; arranged from smallest to largest, they are negative infinity, negative finite nonzero values, positive and negative zero, positive finite nonzero values, and positive infinity.

 
Ryan Deiter
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You guys are awesome.
Thanks,
Ryan Deiter
 
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