Editing Conditional (computer programming) (section)

==== The "dangling else" problem ====
{{Main|Dangling else}}
The <code>else</code> keyword is made to target a specific <code>if–then</code> statement preceding it, but for [[Nesting (computing)|nested]] <code>if–then</code> statements, classic programming languages such as [[ALGOL 60]] struggled to define which specific statement to target. Without clear boundaries for which statement is which, an <code>else</code> keyword could target any preceding <code>if–then</code> statement in the nest, as parsed.
 '''if''' a '''then''' '''if''' b '''then''' s '''else''' s2
can be parsed as
 '''if''' a '''then''' ('''if''' b '''then''' s) '''else''' s2
or
 '''if''' a '''then''' ('''if''' b '''then''' s '''else''' s2)
depending on whether the <code>else</code> is associated with the first <code>if</code> or second <code>if</code>. This is known as the [[dangling else]] problem, and is resolved in various ways, depending on the language (commonly via the <code>end if</code> statement or <code>{...}</code> brackets).