Delphi Basics : DownTo command

DelphiBasics

DownTo
Keyword

Prefixes an decremental for loop target value

1	keyword DownTo(for Variable := Integer Expression downto Integer Expression do Statement;
2	for Variable := Char Expression downto Char Expression do Statement;
3	for Variable := Enum Expression downto Enum Expression do Statement;

Description

The DownTo keyword prefixes the target value Expression in a For loop.

The DownTo expression maybe an Integer, Character or Enumeration type.

See the For keyword for full details. The examples illustrate the three expression types.

Related commands

Begin		Keyword that starts a statement block
End		Keyword that terminates statement blocks
For		Starts a loop that executes a finite number of times
To		Prefixes an incremental for loop target value

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Example code : Integer for loop

var
  i : Integer;

begin
  // Loop 5 times
  for i := (10 div 2) DownTo 1 do
    ShowMessage('i = '+IntToStr(i));
end;

Show full unit code

  i = 5
  i = 4
  i = 3
  i = 2
  i = 1

Example code : Character for loop

var
  c : char;
begin
  // Loop 5 times
  for c := 'E' DownTo 'A' do
    ShowMessage('c = '+c);
end;

Show full unit code

  c = E
  c = D
  c = C
  c = B
  c = A

Example code : Enumeration for loop

var
  suit : (Hearts, Clubs, Diamonds, Spades);
begin
  // Loop 3 times
  for suit := Diamonds DownTo Hearts do
    ShowMessage('Suit = '+IntToStr(Ord(suit)));
end;

Show full unit code

  Suit = 2
  Suit = 1
  Suit = 0