Ternary operator associativity in C# - can I rely on it?

user_41360 0
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Ahh, don't you just love a good ternary abuse? :) Consider the following expression:

true ? true : true ? false : false

For those of you who are now utterly perplexed, I can tell you that this evaluates to true. In other words, it's equivalent to this:

true ? true : (true ? false : false)

But is this reliable? Can I be certain that under some circumstances it won't come to this:

(true ? true : true) ? false : false

Some might say - well, just add parenthesis then or don't use it altogether - after all, it's a well known fact that ternary operators are evil!

Sure they are, but there are some circumstances when they actually make sense. For the curious ones - I'm wring code that compares two objects by a series of properties. It would be pretty nice if I cold write it like this:

obj1.Prop1 != obj2.Prop1 ? obj1.Prop1.CompareTo(obj2.Prop1) :
obj1.Prop2 != obj2.Prop2 ? obj1.Prop2.CompareTo(obj2.Prop2) :
obj1.Prop3 != obj2.Prop3 ? obj1.Prop3.CompareTo(obj2.Prop3) :
obj1.Prop4.CompareTo(obj2.Prop4)

Clear and concise. But it does depend on the ternary operator associativity working like in the first case. Parenthesis would just make spaghetti out of it.

So - is this specified anywhere? I couldn't find it.

associativity ternary-operator .net c#
5 Answers
x = cond1 ? result1
  : cond2 ? result2
  : cond3 ? result3
  : defaultResult;

vs

if (cond1) x = result1;
else if (cond2) x = result2;
else if (cond3) x = result3;
else x = defaultResult;

I like the first one.

Yes, you can rely on conditional operator associativity. Its in the manual, at the link kindly provided by dcp, stated as "The conditional operator is right-associative", with an example. And, as you suggested and I and others agreed, the fact that you can rely on it allows clearer code.

user_5455570
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