Elaborate Dice Roller

[denialdeliciousbeer]

Hi

I've created a simple dice roller, picture included, which generates a random integer from the value (number of dice) in the textbox.

Now I want to add a new dice roller which is more complex. This dice roller has to generate a number of integers from the value in textbox1. Then it has to select those integers with the highest values, the number of which are determined by the value in textbox2, and add those together to get the result.

I don't expect someone to do my work for me but I don't even know where to start with such a complex process. Any ideas on how I should tackle this problem?

[Abraham Getzler]

You need to read up on lists.

A good online book:

http://www.appinventor.org/book2

Your collection of dice should be kept in a list,

one per item, with each item ranging from 1 to 6.

ABG

[denialdeliciousbeer]

Okay here's my attempt. Could it be pared down to something simpler?

[Taifun]

yes, you could use the for each loop to add n items in the list, in your case with the following parameters

from = 1

to = textbox6.text

by = 1

http://appinventor.mit.edu/explore/ai2/support/blocks/control.html#forrange

Taifun

---

Trying to push the limits of App Inventor! Snippets and Tutorials from Pura Vida Apps by Taifun.         

for each from to

Runs the blocks in the do section for each numeric value in the range starting at from and ending at to, incrementing number by the value of by each time. Use the given variable name, number to refer to the current value. You can change the name number to something else if you wish.

[Abraham Getzler]

Also be merciful to readers of your blocks - 

Rename Textbox6 to something more informative,

like txtDiceCount.

Don't worry, the name change will propagate automatically

from the Designer to all its blocks.

ABG

[denialdeliciousbeer]

Thanks for the loop, it's a lot simpler and works perfectly. Now onto the difficult part, selecting, from the list, integers by their max value, the number of which selected is determined by one of the numbers of dice rolled. After looking through the board and some of the tutorials I came up with this.

As you can probably tell, it does not work. Probably for an obvious reason that escapes me.

[Taifun]

to simplify even a little bit more, set the list to empty list in the beginning like this

 selecting, from the list, integers by their max value, the number of which selected is determined by one of the numbers of dice rolled

unfortunately I did not understand what you are trying to do

but probably an example could help: 

lets assume dieroll1=2 and dieroll2=3, which means, we have a list with 5 die let's say like this:  6,3,5,6,1

now how should the result look like?

Taifun

[Abraham Getzler]

Names are important.

Without a good scheme for naming your variables,

you (and we) have no hope of understanding

your blocks.

Build up your names from multiple parts, reflecting the roles

and attributes of the thing they name.

These name parts have special uses:

index = position in a list

list tells you it is a list

value tells you it is a value, not an index

die = which die this is

roll = step in the game

component = thing on the screen

ABG

[denialdeliciousbeer]

Sorry it makes sense to me.  In effect what I am attempting to do is the following:-

dieroll1 is the first set of dice being rolled

dieroll2 is the second set of dice being rolled

The results of both go into list global melresult

A number of integers from global melresult are selected to go into global melselection.

The number of them selected is equal to the value of dieroll1. 

They are selected in order of highest to lowest.

The integers in global melselection are then added together to give a total value for local melresult which goes into the melresult label.

I will rename them for the next set of images to be clearer.

[Abraham Getzler]

I suggest a Divide and Conquer approach.

Write a few value procedures you will need ...

SumOfList(list) = sum of the values in the given list

(use a local variable with running subtotal, initially 0)

IndexOfMaxOfList(list) = the index of the biggest value in the given list

(use a local variable with running max, initially 0

and another local variable with running index of max, initially 0)

Also you will probably need extra lists with names like

Candidates and Chosen, during the process of choosing

the high dice and eliminating them from future consideration.

There's a Copy List block that might come in useful.

ABG

[denialdeliciousbeer]

Right here's my second attempt. I came at the problem from a different angle.

The procedure should, for each item in the dicelist (the random values generated by the diceroller) compare it to global maxnumber which starts at 6.

If the item is equal to that value then it adds it to the second list, diceselection, and then removes the item from the first list, dicelist.

Then it sets the global maxnumber value to 5.

If the dicelist has no items left then the next procedure starts,dicesum.

If the dicelist does have items in it then it starts the procedure again with the new global maxnumber of 5.

It loops until all of the items in dicelist have been assigned to diceselection.

The idea is that that diceselection should be ordered from highest to lowest so that the dicesum procedure can then total the first x items in the list.

Again it doesn't work. At best I get an error of --empty string-- at worst it crashes the emulator.

[Taifun]

why don't you just order the list descending?

How to sort a list using the webviewer(!)

as already said, an example would help to understand what you are trying to do...

[denialdeliciousbeer]

The result should look like

6 6 5 3 1

Does the webviewer solution require internet access? It looks like it does and that wouldn't work for me.

[Taifun]

Does the webviewer solution require internet access?

no, you also can set the URL to a local webpage first, see also 

How to read a HTML page stored as asset inside of App Inventor

Taifun

[denialdeliciousbeer]

Okay so the dicesorter works. It will take the list and sort it into another list in descending order.

So see the attachment for the next step, the sum procedure. 

It should total the first few list values, the number of which is determined by the value of the first set of dice rolled.

e.g. if the list looks like this 6 6 5 3 1. If the first sets value was 1 it will return 6. If the first sets value was 2 it will return 12, 3 would be 17 etc.

It works properly most of the time but if the value of the first set is 1 it occasionally returns a sum that is larger than 6. I cannot see why it would do so as all the global and local variables are cleared or reset after every operation. Any ideas on where I am going wrong?

[Taifun]

probably there is an issue in your current version if there are two die with the same value?
try the for each number from to loop instead

http://appinventor.mit.edu/explore/ai2/support/blocks/control.html#forrange

Taifun