Difference between revisions of "Basic Pascal Tutorial/Chapter 3/REPEAT..UNTIL"
From Lazarus wiki
Jump to navigationJump to search (Use pascal highlighter) |
m (rewrite in more idiomatic English) |
||
Line 2: | Line 2: | ||
{{TYNavigator|WHILE..DO|FOR..IN}} | {{TYNavigator|WHILE..DO|FOR..IN}} | ||
− | REPEAT..UNTIL | + | REPEAT...UNTIL |
− | The | + | The repeat .. until construct is termed a ''post''-test loop, because the controlling condition is tested ''after'' each iteration of the loop. |
+ | |||
+ | It has the following syntax: | ||
<syntaxhighlight lang=pascal> | <syntaxhighlight lang=pascal> | ||
repeat | repeat | ||
statement1; | statement1; | ||
− | statement2 | + | // statement2; |
+ | // further statements... | ||
until BooleanExpression; | until BooleanExpression; | ||
</syntaxhighlight> | </syntaxhighlight> | ||
− | + | A <tt>repeat</tt> loop encloses its executed statements, which means they do not need to be further enclosed in a <tt>begin ... end<tt> block. Note that a repeat loop continues until its controlling Boolean expression is <tt>TRUE</tt>; whereas the <tt>while</tt> loop continues until its Boolean expression is <tt>FALSE</tt>. | |
− | + | Use a <tt>REPEAT</tt> loop when the looping statement(s) must execute at least once, whatever the initial value of the controlling Boolean condition. | |
{{TYNavigator|WHILE..DO|FOR..IN}} | {{TYNavigator|WHILE..DO|FOR..IN}} |
Revision as of 22:35, 20 November 2020
│
български (bg) │
English (en) │
français (fr) │
日本語 (ja) │
中文(中国大陆) (zh_CN) │
REPEAT...UNTIL
The repeat .. until construct is termed a post-test loop, because the controlling condition is tested after each iteration of the loop.
It has the following syntax:
repeat
statement1;
// statement2;
// further statements...
until BooleanExpression;
A repeat loop encloses its executed statements, which means they do not need to be further enclosed in a begin ... end block. Note that a repeat loop continues until its controlling Boolean expression is TRUE; whereas the while loop continues until its Boolean expression is FALSE.
Use a REPEAT loop when the looping statement(s) must execute at least once, whatever the initial value of the controlling Boolean condition.