Char: what changed
Revision 0 to 1. Removed lines have a minus sign; added lines have a plus sign.
Title: Char
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| 1 | + | A **char** stores a single character and is currently one byte, and [[AnsiChar]] is an alias for it. However, in the future, **char** may become the same as a [[WideChar]]. For now, [[Byte|byte]] and char are almost identical - one byte (8-bits) in size. However, a char can only be used as a character, or as part of a [[String|string]] type, and cannot be used in an arithmetic expression, while a byte can only be referred to as a numeric type. | |
| 2 | + | ||
| 3 | + | For example: | |
| 4 | + | ||
| 5 | + | ``` pascal | |
| 6 | + | var ch: char; | |
| 7 | + | c: byte; | |
| 8 | + | ||
| 9 | + | begin | |
| 10 | + | ch := 'A'; c := 65; { are the same action, and are legal } | |
| 11 | + | ch := 65; c := 'A'; { while they are internally the same values, | |
| 12 | + | direct assignment between Chars and Bytes is illegal } | |
| 13 | + | end. | |
| 14 | + | ``` | |
| 15 | + | ||
| 16 | + | The use of char or byte as a data type provides better documentation as to the purpose of the use of the particular variable. The char type can be [[coersion|coerced]] to byte by using the [[Ord|ord]] function. Byte type values can be coerced to char by using the [[Chr|chr]] function. | |
| 17 | + | ||
| 18 | + | type chars functions follows the [[ASCII]]. | |
| 19 | + | ||
| 20 | + | The above program corrected to legal use: | |
| 21 | + | ||
| 22 | + | ``` pascal | |
| 23 | + | var ch: char; | |
| 24 | + | c: byte; | |
| 25 | + | ||
| 26 | + | begin | |
| 27 | + | ch := 'A'; c := 65; { are the same action, and are legal } | |
| 28 | + | ch := chr(65); c := ord('A'); { now legal } | |
| 29 | + | ch := Char(65); c := Byte('A'); { also legal and guaranteed to happen at compile time } | |
| 30 | + | end. | |
| 31 | + | ``` | |
| 32 | + | ||
| 33 | + | A [[For|FOR]] loop control variable can be any enumerable (capable of being put into one-to-one correspondence with the positive integers) which allows a CHAR variable to be used in that regard: | |
| 34 | + | ||
| 35 | + | ``` pascal | |
| 36 | + | var | |
| 37 | + | Loop: Char; | |
| 38 | + | ||
| 39 | + | begin | |
| 40 | + | for Loop := 'a' to 'c' do WriteLn(Loop); | |
| 41 | + | end. | |
| 42 | + | ``` | |
| 43 | + | ||
| 44 | + | ## See also | |
| 45 | + | ||
| 46 | + | - [[Character and string types]], a detailed reference covering internal memory layout and access options. | |
| 47 | + | ||
| 48 | + | --- | |
| 49 | + | *From the Free Pascal wiki, page "Char", as it stood on 2023-10-17 after a change by FPC user, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).* |