Difference between revisions of "Control flow"

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The underlying [[Central Processing Unit|CPU]]'s [[instruction set]] has a number of '''transfer of control''' primitives: jump/branch, both un-conditional as well as [[conditional branch]]es; and [[subroutine]] calls.
 
The underlying [[Central Processing Unit|CPU]]'s [[instruction set]] has a number of '''transfer of control''' primitives: jump/branch, both un-conditional as well as [[conditional branch]]es; and [[subroutine]] calls.
  
[[Programming language]]s often add additional mechanisms, particularly '''block structures''', in which a group of instructions are treated as a unit for various control mechanisms (e.g. loop control, if-then-else constructs, etc).
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[[Programming language]]s often add additional mechanisms, particularly '''block structures''', in which a group of instructions are treated as a unit for various control mechanisms (e.g. [[loop]]s, if-then-else constructs, etc).
  
 
Blocks are also often used to control the [[scope]] over which variables (particularly [[local variable]]s) are accessible.
 
Blocks are also often used to control the [[scope]] over which variables (particularly [[local variable]]s) are accessible.
  
 
[[Interrupt]]s and [[exception]]s also divert the flow of control in a computer, but at times which are not always predictable.
 
[[Interrupt]]s and [[exception]]s also divert the flow of control in a computer, but at times which are not always predictable.

Revision as of 14:47, 6 November 2017

Control flow refers to the means for controlling the order in which sections of a program are executed.

The underlying CPU's instruction set has a number of transfer of control primitives: jump/branch, both un-conditional as well as conditional branches; and subroutine calls.

Programming languages often add additional mechanisms, particularly block structures, in which a group of instructions are treated as a unit for various control mechanisms (e.g. loops, if-then-else constructs, etc).

Blocks are also often used to control the scope over which variables (particularly local variables) are accessible.

Interrupts and exceptions also divert the flow of control in a computer, but at times which are not always predictable.