Editing Control flow (section)

=== Infinite loops ===
{{main article|Infinite loop}}
[[Infinite loop]]s are used to assure a program segment loops forever or until an exceptional condition arises, such as an error. For instance, an event-driven program (such as a [[Server (computing)|server]]) should loop forever, handling events as they occur, only stopping when the process is terminated by an operator.

Infinite loops can be implemented using other control flow constructs. Most commonly, in unstructured programming this is jump back up (goto), while in structured programming this is an indefinite loop (while loop) set to never end, either by omitting the condition or explicitly setting it to true, as <code>while (true) ...</code>. Some languages have special constructs for infinite loops, typically by omitting the condition from an indefinite loop. Examples include Ada (<code>loop ... end loop</code>),<ref>[[b:Ada Programming/Control#Endless Loop|Ada Programming: Control: Endless Loop]]</ref> Fortran (<code>DO ... END DO</code>), Go (<code>for { ... }</code>), and Ruby (<code>loop do ... end</code>).

Often, an infinite loop is unintentionally created by a programming error in a condition-controlled loop, wherein the loop condition uses variables that never change within the loop.