Difference between revisions of "If and Then"

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<code>condition</code> is a [[boolean]] expression that evaluates to [[True|true]] xor [[False|false]].
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<code>condition</code> is a [[Boolean|boolean]] expression that evaluates to [[True|true]] xor [[False|false]].
 
<code>true_statement</code> is executed if <code>condition</code> evaluates to <code>true</code>.
 
<code>true_statement</code> is executed if <code>condition</code> evaluates to <code>true</code>.
 
<code>false_statement</code> is executed if <code>condition</code> evaluates to <code>false</code>.
 
<code>false_statement</code> is executed if <code>condition</code> evaluates to <code>false</code>.
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=== multiple statements in <code>if then</code> branch ===
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=== Multiple statements in <code>if then</code> branch ===
  
If you need two or more statements for <code>true_statement</code> or <code>false_statement<code>, enclose them within a <code>[[Begin|begin]] … [[End|end]]</code> [[Block]] (compound statement).
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If you need two or more statements for <code>true_statement</code> or <code>false_statement</code>, enclose them within a <code>[[Begin|begin]] … [[End|end]]</code> [[Block]] (compound statement).
  
 
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== external references ==
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== See also ==
  
* official documentation: [https://www.freepascal.org/docs-html/ref/refsu57.html Reference guide: § “The <code>If..then..else</code> statement”]
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* Official documentation: [https://www.freepascal.org/docs-html/ref/refsu57.html Reference guide: § “The <code>If..then..else</code> statement”]
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* [[IF]], Tao Yue, Object Pascal Introduction
  
 
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[[Category:Pascal]]
 
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[[Category:Control Structures]]
 
[[Category:Control Structures]]

Revision as of 10:07, 24 January 2018

English (en)

The if keyword precedes a condition, must be followed by then and a statement. The statement may optionally be followed by else and another statement.


If then

if condition
	then true_statement
	else false_statement;

condition is a boolean expression that evaluates to true xor false. true_statement is executed if condition evaluates to true. false_statement is executed if condition evaluates to false. A compile-time error occurs if the type of condition does not evaluate to a boolean value.


Multiple statements in if then branch

If you need two or more statements for true_statement or false_statement, enclose them within a begin … end Block (compound statement).

if boolean_condition then
begin
	statement_zero;
	statement_one;
	statement_two;
end;


See also


Keywords: begindoelseendforifrepeatthenuntilwhile