? 1.0 : 0.0 - What does this mean?

Question

Maybe a stupid question for you, but I found a site where this source was given with no further info. I searched with google but I got no useful suggestions.

I want to know what this line actually does. Give me a link or the name of this function? so I can look it up myself.

Thank you :)

y += (x<= uz ? 1.0 : 0.0) * radius;

I know what += and * do, but the rest is a huge questionmark

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Conditional_Operator — Alex K., Jun 24 '13 at 12:54

score 3 · Accepted Answer · edited Jun 24 '13 at 13:01

3

It is a ternary operator.

Conditional (Ternary) Operator (?:)

Returns one of two expressions depending on a condition.
test ? expressionIfTrue : expressionIfFalse

With your code it is the same as:

if (x<uz) {
  y += radius;
} else {
  y += 0;
}

edited Jun 24 '13 at 13:01

Umur Kontacı

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answered Jun 24 '13 at 12:54

epascarello

204,599
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score 2 · Answer 2 · answered Jun 24 '13 at 12:55

2

That is a ternary operator. Basically this translates to:

var y;
// ...

if( x <= uz ) {
  y += 1.0 * radius;
} else {
  y += 0.0 * radius;
}

answered Jun 24 '13 at 12:55

Sirko

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? 1.0 : 0.0 - What does this mean?

2 Answers2