To

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Keyword used to indicate the final value of the control value in a For loop, and that the loop is to increment the control variable by 1 on each loop. The value specified by TO should be greater than the initial value of the for loop.

For to do

var i : integer;
    begin
     for i := 1 to 10000 do
       begin
         //...
       end;
    end;

The for to allow to execute code repeatedly for a fixed number of times.

Basic example

var
      loopValue, startValue, endValue, resultValue: integer;
    begin
      startValue := 10;
      endValue := 11;
      resultValue := 0;
      for loopValue := startValue to endValue do
        begin
          resultValue := loopValue + resultValue;
        end;
    end;

The loop execute two times and variable resultValue value is 21.

Start and end value same

var
      loopValue, startValue, endValue, resultValue: integer;
    begin
      startValue := 10;
      endValue := 10;
      resultValue := 0;
      for loopValue := startValue to endValue do
        begin
          resultValue := loopValue + resultValue;
        end;
    end;

The loop execute one time and variable resultValue value is 10.

Start value bigger than end value

var
      loopValue, startNumber, endNumber, resultValue: integer;
    begin
      startValue := 10;
      endValue := 9;
      resultValue := 0;
      for loopValue := startValue to endValue do
        begin
          resultValue := loopValue + resultValue;
        end;
    end;

The loop execute none time and variable resultValue value is 0.

Note that the value of the "for loop variable" is undefined after a loop has completed or if a loop is not executed at all. However, if the loop was terminated prematurely with an exception or a break (or even a goto statement), the loop variable retains the value it had when the loop was exited.

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• Downto

From the Free Pascal wiki, page "To", as the Internet Archive kept it on 2024-09-20, last changed on 2024-08-15. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.