Weird Operators

I have ‘equal-equal’ imprinted into my mind lol. ‘Equal’ just doesn’t make any sense to me anymore, for some reason :stuck_out_tongue:

Useless programming language trivia:

Some languages actually do have = as the ‘is equal to’ sign.
Usually those languages use something like := (e.g. ALGOL, Pascal) or <- (e.g. R) for assignment.
It’s definitely less popular though.

Technically it’s also possible to use the = for both (I’ve written a parser that does that before), but I don’t know of any languages that actually do that offhand.

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That is quite the questionable ‘equal-equal.’

That’s not the equality test, that’s the assignment operator.

E.g. (Pascal)

if (i = 4) then
  x := 10
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Why don’t they just make it the other way around? I guess I could see a colon being somewhat of an ‘is equal to’ thing.

Probably to make it more in-keeping with what people are taught in maths.

It’s easier to introduce a new operator for assignment than to teach people to learn that = now means ‘assignment’ and == should mean ‘equals’ because it’s harder to unlearn what you’re used to if you’ve never used anything else.

Things get even weirder when you consider not-equal operators too.
Some use !=, some use /= (which is ‘divide by’ in some languages), and some use <> (which also sometimes has a different use in other languags).

C++20 added the <=> - the three-way comparison operator. It:

  • Evaluates to a negative value if the left hand side is less than the right hand side.
  • Evaluates to a positive value if the left hand side is greater than the right hand side.
  • Evaluates to zero if both sides are equal.
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If only Arduino had C++20 :moyai:

I suspect it’s possible to configure the compiler to use C++20, but I don’t know if it could be done using the Arduino IDE.

I have done countless programs using both and you get used to it either way. The only thing that sometimes catches me out is if (x=1) instead of if (x==1).