Question

Can the following expression be simplified?

(M == null && C == null) ||
(M != null && C != null && D == C)

Mathematically I know this can’t be simplified and I checked on WolframAlpha to confirm this, but I was wondering if it might be possible with use of one of the boolean logical operators (&, |, ^), to make that condition shorter. I’ve tried to think of ways but I’m having a mental block… is this actually possible to shorten?

Answer 1

No, it can’t be shortened.

As Ferdinand Liu observes, your expression is true in two cases:

• Both M and C are null, or
• Both M and C are not null, and C and D are equal.

You need to check both M and C in both conditions, so you can’t simplify the expression.

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Interesting but only slightly-related note:

If you didn’t need to check C and D for equality, then the expression would be

(M != null && C != null) || (M == null && C == null)

and this can be simplified to

!((M == null) ^ (C == null))

which is true when M and C have the same “null-ness.”