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NaN

The special float value meaning "no sensible answer", such as 0 / 0; it is not equal to anything, not even itself.

A NaN has an all-ones exponent field and a nonzero fraction; invalid operations (0/0, inf - inf, sqrt(-1)) produce one, most operations propagate it, and every ordered comparison with a NaN is false while != is true.

Examples

  • 0.0 / 0.0 gives NaN, and NaN == NaN is false.

See also

exponent field floating-point infinity quiet NaN signaling NaN
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