Editing Control flow (section)

{{Short description|Execution order of computer commands}}
{{Distinguish|Flow control (data)}}
{{Loop constructs}}<!-- DO NOT remove. Discuss navigation concept at [[Talk:Do while loop#Helpbox experiment]] -->
In [[computer science]], '''control flow''' (or '''flow of control''') is the order in which individual [[Statement (computer science)|statements]], [[Instruction (computer science)|instructions]] or [[function call]]s of an [[imperative programming|imperative]] [[computer program|program]] are [[Execution (computing)|executed]] or evaluated. The emphasis on explicit control flow distinguishes an ''[[imperative programming]]'' language from a ''[[declarative programming]]'' language.

Within an imperative [[programming language]], a ''control flow statement'' is a statement that results in a choice being made as to which of two or more paths to follow. For [[Strict programming language|non-strict]] functional languages, functions and [[language construct]]s exist to achieve the same result, but they are usually not termed control flow statements.

A set of statements is in turn generally structured as a [[Block (programming)|block]], which in addition to grouping, also defines a [[lexical scope]].

[[Interrupt]]s and [[Signal (computing)|signals]] are low-level mechanisms that can alter the flow of control in a way similar to a [[subroutine]], but usually occur as a response to some external stimulus or event (that can occur [[Asynchronous systems|asynchronously]]), rather than execution of an ''in-line'' control flow statement.

At the level of [[machine language]] or [[assembly language]], control flow instructions usually work by altering the [[program counter]]. For some [[central processing unit]]s (CPUs), the only control flow instructions available are conditional or unconditional [[Branch (computer science)|branch]] instructions, also termed jumps.