Delphi Basics : Inc command

DelphiBasics

Inc
Procedure

Increment an ordinal variable

System unit

1	procedure Inc(var Variable Ordinal variable);
2	procedure Inc (var Variable Ordinal variable; Count Integer;

Description

The Inc procedure increments the ordinal Variable parameter passed to it.

You can increment :

Characters
Non-floating number types
Enumeration types
Pointers

The increment is by the base size of the unit. For example, incrementing a Pointer will be by 2 bytes if the pointer points to Words.

Version 1 of Inc increments by 1 unit.

Version 2 of Inc increments by Count units.

Notes

Inc is equivalent in performance to simple addition, or the Succ procedure.

Count can be negative.

Related commands

Dec		Decrement an ordinal variable
Pred		Decrement an ordinal variable
Sqr		Gives the square of a number
Sqrt		Gives the square root of a number
Succ		Increment an ordinal variable
Sum		Return the sum of an array of floating point values

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Example code : Incrementing characters, numbers and enumerations

type
  TSuit = (Hearts, Clubs, Diamonds, Spades);
var
  Character : char;
  Number    : Integer;
  Card      : TSuit;

begin
  // We can increment characters
  Character := 'A';

  ShowMessage('Character : '+Character);
  Inc(Character);
  ShowMessage('Character+1 : '+Character);

  // We can increment numbers
  Number := 23;

  ShowMessage('Number : '+IntToStr(Number));
  Inc(Number, 5);
  ShowMessage('Number+5 : '+IntToStr(Number));

  // We can increment enumerations
  Card := Clubs;

  ShowMessage('Card starts at Clubs');
  Inc(Card);
  if Card = Hearts then ShowMessage('Card is now Hearts');
  if Card = Clubs then ShowMessage('Card is now Clubs');
  if Card = Diamonds then ShowMessage('Card is now Diamonds');
  if Card = Spades then ShowMessage('Card is now Spades');
end;

Show full unit code

  Character : A
  Character+1 : B
  Number : 23
  Number+5 : 28
  Card starts at Clubs
  Card is now Diamonds