Plus
From Lazarus wiki
Revision as of 00:41, 17 October 2019 by Kai Burghardt (talk | contribs) ({$modeSwitch arrayOperators} since FPC 3.2.0)
│
English (en) │
suomi (fi) │
français (fr) │
русский (ru) │
+
The symbol +
(pronounced “plus”) is used to:
- explicitly indicate the positive sign of a number,
- add two numbers resulting to a number,
- form a union of sets,
- (FPC) concatenate two strings (or characters; except
pchar
). - if
{$modeSwitch arrayOperators+}
(default in{$mode Delphi}
), concatenate arrays (since FPC 3.2.0) - enable a feature in a
{$modeSwitch}
1program plusDemo(input, output, stderr);
2
3var
4 x: longint;
5 g: set of (foo, bar);
6 m: string;
7begin
8 // unary operator: positive sign
9 x := +7; // x becomes positive 7
10 x := +$100; // x becomes 256
11 // (dollar sign denotes hexadecimal base)
12
13 // addition
14 x := 7 + 7; // x becomes 14
15 x := 7 + 7 + 7 + 7 + 7 + 7; // x becomes 42
16
17 // union of sets
18 g := [foo] + [bar]; // g becomes [foo, bar]
19
20 // concatenation of strings and/or characters (FPC/Delphi extension)
21 m := 'Hello ' + 'world!'; // m becomes 'Hello world!'
22end.
The plus sign is also a unary operator.
One can write such stupid expressions as ++++++++++++++42
which will evaluate to positive 42.
In ASCII, the character code decimal 43
(or hexadecimal 2B
) is defined to be +
(plus sign).
see also
system.add
system.concat
returns concatenation of stringsstrings.strcat
returns concatenation ofpchar
strings
single characters |
|
character pairs |
|