what does "0" stand for in conditional operator?

Question

Consider the following code:

  i = (i == array.length-1) ? 0 : i + 1;

As I understand, the conditional operator works as follows:

booleanCondition ? executeThisPartIfBooleanConditionIsTrue : executeThisPartIfBooleanConditionIsFalse

What does 0 execute?

Not really clear what you question is - could you elaborate a bit? — Mathias Bader, May 20 '18 at 13:33
`( condition) ? result for true : result for false` ... resulting in a value. That is all there is to this. — GhostCat, May 20 '18 at 13:35
It is not about **execution**. The ternary operator computes a **value**. The two different "branches" represent the **expressions** that are returned, based on the condition. — GhostCat, May 20 '18 at 13:36
@GhostCat Strickly speaking this is NOT a duplicate since it is "what is the "0" called" not what is a ternary or conditional operator — Mark Schultheiss, May 20 '18 at 13:49
The point is that the OP has a wrong understanding of ternary operators. There is no execution here. Just expressions evaluating to values. So linking to "what are ternary expressions" seems fine to me. — GhostCat, May 20 '18 at 14:36

Mark Schultheiss · Accepted Answer · 2018-05-20T13:42:43.133

0

I do not think the "positive conditional test result" really has a formal name.

?: Ternary (shorthand for if-then-else statement)

using a boolean example

isConditionTrue = 1 == 2 ? true : false;

this in your example

i = (i == array.length-1) ? 0 : i + 1;

has the same result as

if (i == array.length-1)
{i= 0 ;}
else {i = i + 1;}

edited May 20 '18 at 13:42

answered May 20 '18 at 13:35

Mark Schultheiss

Despite the down-vote I stand by my answer of "it really has no formal name" for the positive conditional result. – Mark Schultheiss May 20 '18 at 13:50

score -1 · Answer 2 · answered May 20 '18 at 13:34

This is known as the Elvis Operator (see [https://en.wikipedia.org/wiki/Elvis_operator]) and given the following example:

x = A ? B : C;

... it means that if A is evaluated to 'true' than x gets assigned the value B otherwise it gets assigned the value C.

In your example it means, that if 'i==array.length-1' then 'i' is set to '0' otherwise 'i' is set to 'i+1'.

2 Answers2