31 lines
1.2 KiB
Plaintext
31 lines
1.2 KiB
Plaintext
Floating point math is imprecise because of the challenges of storing such values in a binary representation. Even worse, floating point math is not associative; push a <code>Float</code> or a <code>Double</code> through a series of simple mathematical operations and the answer will be different based on the order of those operation because of the rounding that takes place at each step.
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Even simple floating point assignments are not simple:
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----
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var f: Float = 0.1 // 0.1000000014901161193847656
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var d: Double = 0.1 // 0.1000000000000000055511151
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----
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Therefore, the use of the equality (<code>==</code>) and inequality (<code>!=</code>) operators on <code>Float</code> or <code>Double</code> values is almost always an error.
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This rule checks for the use of direct and indirect equality/inequailty tests on floats and doubles.
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== Noncompliant Code Example
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----
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var myNumber: Float = 0.3 + 0.6
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if myNumber == 0.9 { // Noncompliant. Because of floating point imprecision, this will be false
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// ...
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}
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if myNumber <= 0.9 && myNumber >= 0.9 { // Noncompliant indirect equality test
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// ...
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}
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if myNumber < 0.9 || myNumber > 0.9 { // Noncompliant indirect inequality test
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// ...
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}
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----
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