B4J Question do while not skip with continue ?

Waldemar Lima · Apr 7, 2022

hello everyone, I'm trying to generate numbers that are not repeated within 4 maps, but the algorithm is not so efficient, despite "it makes sense in my logic", can someone verify if there is no inconsistency with the "continue" inside the Do while ?

algorithm >

B4X:

Sub Process_Globals

    Private Bot1_Cards As Map

End Sub

Sub AppStart (Args() As String)

    Bot1_Cards.Initialize

    For i = 0 To 15
        Bot1_Cards.Put(i,GenerateDeckCardsUnique)
    Next

    Log("------------------------------------")
   
    For i = 0 To Bot1_Cards.Size-1
        Log("1x"&i&"-"&Bot1_Cards.Get(i))
    Next

end sub

Sub GenerateDeckCardsUnique As Int
   
    Dim isLoop As Int = 1
    Dim GeneratedCard As Int
   
    Do While ( isLoop = 1)

        GeneratedCard = Rnd(0,51)
       
        Log("GENERATED NUMBER = "&GeneratedCard)
       
        If (Bot1_Cards.Size>0) Then
            For j = 0 To Bot1_Cards.Size-1
                Log("Card1="&Bot1_Cards.Get(j))
                If (GeneratedCard = Bot1_Cards.Get(j)) Then
                    Log("BOT1 - CARD EXISTS")
                    Continue '
                End If
            Next
        Else
            Log("EMPTY FOR WHILE")  
        End If

        isLoop = 0
        Return GeneratedCard
       
    Loop


End Sub

Can anyone see the problem that I'm not seeing?

Sandman · Apr 7, 2022

I'm not certain what you want your end-goal is, could it be something like below?

You have a deck of 52 cards (numbered 0-51), and you have four people. Each person should have unique 16 cards on hand in the end.

(I'm ignoring that 16x4 > 52, I assume you're only doing some testing.)

If this is correct, this is what you should do, written as skeleton code:

B4X:

Sub Process_Globals

    Private Deck as List

End Sub


Sub AppStart (Args() As String)

    FillDeck(52)
    ShuffleDeck(1000)

    Log(GetCardsFromDeck(16)) ' Person 1
    Log(GetCardsFromDeck(16)) ' Person 2
    Log(GetCardsFromDeck(16)) ' Person 3
    Log(GetCardsFromDeck(16)) ' Person 4

end sub


Sub FillDeck(size as Int)
   
    ' Fill Deck with values that make sense to you

End Sub


Sub ShuffleDeck(iterations as Int)
   
    ' Loop for number of iterations: (which will decide how random it will be shuffled)
    ' Take card at random position and remove it from Deck, then place it at first position (or last, if that's easier)

End Sub


Sub GetCardsFromDeck(number as Int)
   
    ' Return number of cards from Deck (and also remove them from Deck when doing so)

End Sub

LucaMs · Apr 7, 2022

https://www.b4x.com/android/forum/threads/136776/#content

alwaysbusy · Apr 7, 2022

The continue keyword stops the current iteration (being a For, a While, ...) and starts the next. (as long a j < Bot1_Cards.Size). So, in your case the continue has effect on the For loop, not on the Do While. If you want it to jump out of the For loop, you can use Exit.

Alwaysbusy

B4J Question do while not skip with continue ?

Waldemar Lima

Well-Known Member

Sandman

Expert

LucaMs

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alwaysbusy

Expert

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B4J Question do while not skip with continue ?

Waldemar Lima

Well-Known Member

Sandman

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LucaMs

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alwaysbusy

Expert

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