In Javascript declarations, what does "?" along with ":" mean?

Question

In a Javascript program to convert a Julian day to a calendar day, the following code is seen:

 month = (G<13.5) ? (G-1) : (G-13)
  year = (month<2.5) ? (C-4715) : (C-4716)

I thought these may have been some sort of conditions that changed the values of month or year according to the values of the variables within their declarations My research has returned nothing on these symbols--particularly the "?"--showing up in Javascript code.

For a complete view of the source, visit astronomy.villanova.edu/links/jd.htm

Any help would be greatly appreciated!

Ternary or [conditional operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Conditional_Operator) — mplungjan, Jun 09 '13 at 14:57
As one of the comments said in "Question mark in JavaScript", this is very hard to search within a search engine. My apologies on having a duplicate question! — pkshultz, Jun 09 '13 at 15:04

score 0 · Accepted Answer · answered Jun 09 '13 at 14:57

0

This is called the ternary or conditional operators in javascript

It is a short hand for something like:

if(a ==0){
   b = 1;
}
else{
   b = 0;
}

answered Jun 09 '13 at 14:57

karthikr

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No; it's called the conditional operator. – SLaks Jun 09 '13 at 14:57
@SLaks Please check the posted link. It can be called both – karthikr Jun 09 '13 at 14:59

score 0 · Answer 2 · answered Jun 09 '13 at 14:58

0

variable = if condition is true ? give this answer : otherwise give this one;

so int x = 5; int y = x==5? 10 :12; would mean if x is equal to 5, y would be 10 , otherwise it would be 12

answered Jun 09 '13 at 14:58

Lena Bru

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In Javascript declarations, what does "?" along with ":" mean?

2 Answers2