Difference between revisions of "^"
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<div style="float:left; margin: 0 25px 20px 0; padding:40px; font-size:500%; font-family: Georgia; background-color: #f9f9f9; border: 2px solid #777777;">^</div> | <div style="float:left; margin: 0 25px 20px 0; padding:40px; font-size:500%; font-family: Georgia; background-color: #f9f9f9; border: 2px solid #777777;">^</div> | ||
| + | In [[ASCII]] the character code decimal<syntaxhighlight lang="pascal" enclose="none">94</syntaxhighlight> (or [[Hexadecimal|hexadecimal]] <syntaxhighlight lang="pascal" enclose="none">5E</syntaxhighlight>) is defined to be <syntaxhighlight lang="pascal" enclose="none">^</syntaxhighlight> (circumflex accent). | ||
| + | For any data type, a [[Pointer|pointer]] type for that data can be declared using the operator <syntaxhighlight lang="pascal" enclose="none">^</syntaxhighlight> in front of the data type. | ||
| + | <syntaxhighlight lang="pascal" line highlight="6-7,11,21-22"> | ||
| + | program pointerDemo(input, output, stderr); | ||
| + | type | ||
| + | listItem = record | ||
| + | data: integer; | ||
| + | // next _points_ _to_ a list item | ||
| + | next: ^listItem; | ||
| + | end; | ||
| − | + | var | |
| + | start: ^listItem; | ||
| − | + | begin | |
| + | new(start); | ||
| + | if not assigned(start) then | ||
| + | begin | ||
| + | writeLn(stderr, 'obtaining memory for start failed'); | ||
| + | halt(1); | ||
| + | end; | ||
| + | |||
| + | // _de-reference_ the pointer, follow it | ||
| + | start^.data := 7; | ||
| + | |||
| + | dispose(start); | ||
| + | end.</syntaxhighlight> | ||
| + | |||
| + | {{Symbols}} | ||
| + | |||
| + | [[Category:Code]] | ||
Revision as of 14:15, 24 March 2018
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^
In ASCII the character code decimal94 (or hexadecimal 5E) is defined to be ^ (circumflex accent).
For any data type, a pointer type for that data can be declared using the operator ^ in front of the data type.
1program pointerDemo(input, output, stderr);
2
3type
4 listItem = record
5 data: integer;
6 // next _points_ _to_ a list item
7 next: ^listItem;
8 end;
9
10var
11 start: ^listItem;
12
13begin
14 new(start);
15 if not assigned(start) then
16 begin
17 writeLn(stderr, 'obtaining memory for start failed');
18 halt(1);
19 end;
20
21 // _de-reference_ the pointer, follow it
22 start^.data := 7;
23
24 dispose(start);
25end.
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