Iteration

If you want to activate the same set of nodes multiple times, you can do so with iteration nodes!

For

The For loop iterates a set of nodes, keeping track of a variable that changes every loop.

A For node has 4 inputs and 3 outputs:

  • The first input is the execution input, like all other execution nodes.

  • The second input is the start number, i.e. what value does this variable hold when you start looping?

  • The third input is the end number, i.e. what value does this variable need to reach to stop the loop?

  • The fourth input is the step number, i.e. how much do we increment/decrement this variable every loop?

It’s outputs are:

  • The first output is the loop execution, i.e. the nodes that run every loop.

  • The second output is the variable value.

  • The third output is the after execution, i.e. it is activated when looping has stopped.

Start~#1
For(#1, 1, 10, 1)~#2, #3, #4
Print(#2, #3)

Print(#4, "Done!")

$ decision for.dc

1
2
3
4
5
6
7
8
9
10
Done!

[Variable(num1, Integer, 1052)]
[Variable(num2, Integer, 516)]

[Variable(gcf, Integer, 1)]

> A program to calculate the greatest common factor of num1 and num2,
> given that num1 is greater than num2.
Start~#1

num1~#2
num2~#3

For(#1, 2, #3, 1)~#4, #5, #6
Mod(#2, #5)~#7
Mod(#3, #5)~#8
Equal(#7, 0)~#9
Equal(#8, 0)~#10
And(#9, #10)~#11 > #5 is a factor of num1 AND num2
IfThen(#4, #11)~#12
Set(gcf, #12, #5)

gcf~#13
Print(#6, #13)

$ decision gcf.dc

4

While

The While loop iterates a set of nodes while a condition is true.

It has 2 inputs:

  • The first input is the execution input.

  • The second input is a Boolean that, if true, means it will keep looping.

It also has 2 outputs:

  • The first output is the loop execution, i.e. the nodes that run every loop.

  • The second output is the after execution, i.e. it is activated when looping has stopped.

[Variable(num, Integer, 1)]

Start~#1

num~#2
LessThanOrEqual(#2, 10)~#3

While(#1, #3)~#4, #5
Print(#4, #2)~#6

Add(#2, 1)~#7
Set(num, #6, #7)

Print(#5, "Done!")

$ decision while.dc

1
2
3
4
5
6
7
8
9
10
Done!

[Variable(stop, Integer, 100)]

[Variable(num1, Integer, 0)]
[Variable(num2, Integer, 1)]
[Variable(temp, Integer, 1)]

> A program to calculate the fibonacci numbers from 0 to stop

Start~#1

num1~#2
num2~#3
Add(#2, #3)~#4

stop~#5
LessThanOrEqual(#4, #5)~#6

Print(#1, #2)~#7
Print(#7, #3)~#8

While(#8, #6)~#9
Print(#9, #4)~#10
Set(temp, #10, #4)~#11  > temp = num1 + num2
Set(num1, #11, #3)~#12  > num1 = num2
temp~#13
Set(num2, #12, #13)~#14 > num2 = temp

$ decision fibonacci.dc

0
1
1
2
3
5
8
13
21
34
55
89