[Seed7-users] for

[Thomas M. <tho...@gm...>]

On Mon, 1 Oct 2012 00:37:48 +0200, Renato Lenzi <re...@gm...> wrote:
> I don't fully understand the for sintax, that is i don't understand
> how i can change the increment of the parameter. For example in C# i
> can write:
> 
> for (int x = 0; int < 10; x++)
> {
> ......
> }
> 
> but also:
> 
> for (int x = 0; x < 10; x+=2) or
> for (int x = 0; x < 10; x+=3) etc....
> 
> this way i can modifying the amplitude of iterations.
> Looking at the for declarations in Seed7 manual i guess i have to
> change the amplitude inside the body of the loop. Is there another
> way?

A look at the for declarations in the Seed7 manual shows me, that
I forgot to explain the for-step-statement. Your C# examples
can be written in Seed7 with:

  for x range 0 to 9 step 2 do
    ...
  end for;
  for x range 0 to 9 step 3 do
    ...
  end for;

In the first loop x will have the values 0, 2, 4, 6, 8.
In the second loop x will have the values 0, 3, 6, 9.
For-step-statements with downto are also possible:

  # Here x will have the values 10, 8, 6, 4, 2.
  for x range 10 downto 0 step 2 do
    ...
  end for;
  # Here x will have the values 10, 7, 4, 1.
  for x range 10 downto 0 step 3 do
    ...
  end for;

I hope that this descriptions help you. I will add a more detailed
description of the for-step-statement to the manual, as soon as I
have time to do it.

Regards,
Thomas Mertes