Difference between revisions of "Chr"
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{{Chr}} | {{Chr}} | ||
| − | + | The function <syntaxhighlight lang="pascal" enclose="none">chr</syntaxhighlight> returns the [[Char|<syntaxhighlight lang="pascal" enclose="none">char</syntaxhighlight>]] which has [[ASCII]] value <syntaxhighlight lang="pascal" enclose="none">b</syntaxhighlight>. | |
| + | The signature reads: | ||
| + | <syntaxhighlight lang="pascal"> | ||
| + | function chr(b: byte): char; | ||
| + | </syntaxhighlight> | ||
| + | The function is used and necessary because of Pascal's strong type safety. | ||
| + | With the advent of [[Typecast|typecasts]] a general method became available, though using <syntaxhighlight lang="pascal" enclose="none">chr</syntaxhighlight> is better style. | ||
| − | + | A trivial example shall demonstrate the usage of <syntaxhighlight lang="pascal" enclose="none">chr</syntaxhighlight>: | |
| − | + | <syntaxhighlight lang="pascal"> | |
| + | type | ||
| + | // modern Latin alphabet has 26 letters | ||
| + | latinAlphabetCharacterIndex = 0..25; | ||
| + | {$push} | ||
| + | // let compiler generate code ensuring n >= 0 and n < 26 | ||
| + | {$rangeChecks on} | ||
| + | function getChrInLatinAlphabet(const n: latinAlphabetCharacterIndex): char; | ||
| + | begin | ||
| + | getChrInLatinAlphabet := chr(ord('A') + n); | ||
| + | end; | ||
| + | {$pop} | ||
| + | </syntaxhighlight> | ||
| − | + | [[FPC]] has implemented <syntaxhighlight lang="pascal" enclose="none">chr</syntaxhighlight> as a compiler intrinsic [https://svn.freepascal.org/cgi-bin/viewvc.cgi/tags/release_3_0_4/compiler/ninl.pas?revision=37113&view=markup#l2221 <code>in_chr_byte</code>]. | |
| − | * [[Ord|ord]] | + | |
| + | == see also == | ||
| + | * {{Doc|package=RTL|unit=system|identifier=chr|text=<syntaxhighlight lang="pascal" enclose="none">chr</syntaxhighlight>}} in the system unit reference | ||
| + | * [[Ord|<syntaxhighlight lang="pascal" enclose="none">ord</syntaxhighlight>]] does the reverse operation. | ||
[[Category:Pascal]] | [[Category:Pascal]] | ||
Revision as of 19:06, 12 March 2018
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The function chr returns the char which has ASCII value b.
The signature reads:
function chr(b: byte): char;
The function is used and necessary because of Pascal's strong type safety.
With the advent of typecasts a general method became available, though using chr is better style.
A trivial example shall demonstrate the usage of chr:
type
// modern Latin alphabet has 26 letters
latinAlphabetCharacterIndex = 0..25;
{$push}
// let compiler generate code ensuring n >= 0 and n < 26
{$rangeChecks on}
function getChrInLatinAlphabet(const n: latinAlphabetCharacterIndex): char;
begin
getChrInLatinAlphabet := chr(ord('A') + n);
end;
{$pop}
FPC has implemented chr as a compiler intrinsic in_chr_byte.
