Control Structures: Difference between revisions
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Control structures are features of programming languages that influence the code flow. |
[[Category:Encyclopedia]]'''Control structures''' are features of programming languages that influence the code flow. Examples of control structures are: |
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*loops, which repeat sections of code |
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*conditions, which selectively execute sections of code |
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*exceptions, which help in error handling and avoid causing more problems when there is another problem |
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*jumps (a.k.a. "branches" or "gotos"), which explicitly and usually unconditionally set the next instruction to be executed by the program |
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Examples of these structures can be found on the following pages: |
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==[[Perl]]== |
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===if-then-else=== |
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'''Interpreter:''' Perl 5.8.8 |
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#!/usr/bin/perl -w |
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use strict; |
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my $condition1 = 0; |
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my $condition2 = 1; |
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if ( $condition1 ) { |
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# Do something |
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} |
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if ( $condition1 ) { |
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# Do something |
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} elsif ( $condition2 ) { |
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# Do somethine else |
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} |
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if ( $condition1 ) { |
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# Do something |
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} else { |
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# Do something else |
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} |
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if ( $condition1 ) { |
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# Do something |
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} elsif ( $condition2 ) { |
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# Do something else |
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} else { |
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# Do that other thing |
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} |
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* [[Conditional Structures]] |
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===unless=== |
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* [[Flow Control Structures]] |
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* [[Loop Structures]] |
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'''Interpreter:''' Perl 5.8.8 |
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* [[Exceptions]] |
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#!/usr/bin/perl -w |
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* [[Help:Orphaned code]] |
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use strict; |
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my $condition1 = 0; |
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unless ( $condition1 ) { |
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# Do something |
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} |
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unless ( $condition1 ) { |
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# Do something |
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} else { |
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# Do something else |
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} |
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===while=== |
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'''Interpreter:''' Perl 5.8.8 |
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#!/usr/bin/perl -w |
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use strict; |
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my $condition1 = 0; |
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while ( $condition1 ) { |
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# Do something. |
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# Remember to change the value of condition1 at some point. |
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} |
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===do-while=== |
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'''Interpreter:''' Perl 5.8.8 |
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#!/usr/bin/perl -w |
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use strict; |
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my $condition1 = 0; |
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do { |
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# Do something. |
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# Remember to change the value of condition1 at some point. |
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} while ( $condition1 ); |
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===until=== |
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'''Interpreter:''' Perl 5.8.8 |
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#!/usr/bin/perl -w |
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use strict; |
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my $condition1 = 1; |
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until ( $condition1 ) { |
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# Do something. |
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# Remember to change the value of condition1 at some point. |
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} |
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===do-until=== |
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'''Interpreter:''' Perl 5.8.8 |
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#!/usr/bin/perl -w |
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use strict; |
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my $condition1 = 1; |
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do { |
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# Do something. |
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# Remember to change the value of condition1 at some point. |
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} until ( $condition1 ); |
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===for=== |
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'''Interpreter:''' Perl 5.8.8 |
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#!/usr/bin/perl -w |
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use strict; |
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my $limit = 5; |
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for ( my $iterator = 0; $iterator < $limit; $iterator++ ) { |
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# Do something |
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} |
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===foreach=== |
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'''Interpreter:''' Perl 5.8.8 |
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#!/usr/bin/perl -w |
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use strict; |
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my @array = ( 'Value1', 'Value2', 'Value3' ); |
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foreach (@array) { |
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my $arrayitem = $_; |
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# Do something |
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} |
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Latest revision as of 20:37, 22 October 2008
Control structures are features of programming languages that influence the code flow. Examples of control structures are:
- loops, which repeat sections of code
- conditions, which selectively execute sections of code
- exceptions, which help in error handling and avoid causing more problems when there is another problem
- jumps (a.k.a. "branches" or "gotos"), which explicitly and usually unconditionally set the next instruction to be executed by the program
Examples of these structures can be found on the following pages: