[[Property:modification_date|Wed, 11 Sep 2019 23:28:26 GMT]]
[[Property:publication_date|Wed, 11 Sep 2019 23:28:26 GMT]]
[[Property:uuid|C652AC71-8BAD-4387-A46C-21C9F5C3A68F]]
[[Property:weight|0]]
[[Property:title|Conditional expression]]
[[Property:link_title|Conditional]]

[[Eiffel_programming_language_syntax#Conditionals|Conditional expressions]] compute a value using different expressions depending on one or more conditions. If all expressions have the same type, the conditional expression as a whole has this type as well:

<e>
   if time < noon then
      "Good morning"
   elseif time < evening then
      "Good afternoon"
   else
      "Good evening"
   end
</e>

has type `STRING`.

If the types of the expressions are different, the [[Types#Common_ancestor_types|common ancestor type]] is used as a type of the whole expression.

<e>
   if time < noon then
      "Good morning"
   else
      Void
   end
</e>

has type `detachable STRING`.