Difference between revisions of "^"

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If it is a typed <syntaxhighlight lang="pascal" enclose="none">pointer</syntaxhighlight> operations and syntax for that type are valid, e.g. [[Becomes|assignment]] in the following example.
 
If it is a typed <syntaxhighlight lang="pascal" enclose="none">pointer</syntaxhighlight> operations and syntax for that type are valid, e.g. [[Becomes|assignment]] in the following example.
  
 
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<syntaxhighlight lang="pascal" line highlight="6-7,11,21-22">
 
<syntaxhighlight lang="pascal" line highlight="6-7,11,21-22">
 
program pointerDemo(input, output, stderr);
 
program pointerDemo(input, output, stderr);

Revision as of 19:01, 3 April 2018

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^

In ASCII the character code decimal 94 (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.

A pointer can be followed by appending a ^ to the identifier. Instead of having the memory address in your hands, you will look at the memory content at that address. If it is a typed pointer operations and syntax for that type are valid, e.g. assignment in the following example.


 1program pointerDemo(input, output, stderr);
 2
 3type
 4	listItem = record
 5		payload: 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, i.e. follow it
22	start^.payload := 7;
23	
24	dispose(start);
25end.

see also


navigation bar: topic: Pascal symbols
single characters

+ (plus)  •  - (minus)  •  * (asterisk)  •  / (slash)
= (equal)  •  > (greater than)  •  < (less than)
. (period)  •  : (colon)  •  ; (semi colon)
^ (hat)  •  @ (at)
$ (dollar sign)  •  & (ampersand)  •  # (hash)
' (single quote)

character pairs

<> (not equal)  •  <= (less than or equal)  •  := (becomes)  •  >= (greater than or equal)

 •  >< (symmetric difference)  •  // (double slash)