When randomizing numbers, how do I prevent the number to reoccur?

[Wintermini]

What is it you are trying to achieve?
I'm trying to create a quiz I got the randomizing questions part with the help of arrays, but sometimes, the question will repeat itself. I don't want that.


What is the problem you are having?
- questions (or numbers either way...) are repeated -__-
- how do i calculate the score for this quiz as well?
- how do I stop this quiz?!?! T_T omg i'm so lost and helpless


Describe what you have tried to solve this problem
I tried to take out the looping process out of the code, but I don't think it's helping :\


Post any relevant code (You may choose to attach the file instead of posting the code if it is too long)

Turing:

var q : array 0 .. 5 of int q(0) := Pic.FileNew("q3.bmp") q(1) := Pic.FileNew("q4.bmp") q(2) := Pic.FileNew("q6.bmp") q(3) := Pic.FileNew("q7.bmp") q(4) := Pic.FileNew("q8.bmp") q(5) := Pic.FileNew("q9.bmp") if x >= 450 and x <= 800 and y >= 400 and y <= 450 then      pic:= Pic.FileNew ("quizbackground2.jpg")     if pic = 0 then     put "Unable to load JPG: ", Error.LastMsg     return     end if        Pic.Draw (pic, 0, 0, picCopy)         var tmp : int := Rand.Int(0, 5)     Pic.Draw(q(tmp), 300, 200, picMerge)     loop     if tmp = 0 then         Draw.Box (300, 200, 510, 250, black)             loop               Pic.Draw(q(0), 300, 200, picMerge)               buttonwait ("down", x, y, bnum, bud)               cls               if not (x >= 300 and x <= 510 and y >= 200 and y <= 250) then                   pic:= Pic.FileNew ("quizbackground2.jpg")                   if pic = 0 then                   put "Unable to load JPG: ", Error.LastMsg                   return                   end if                      Pic.Draw (pic, 0, 0, picCopy)                            pic:= Pic.FileNew ("hintq3.bmp")                   if pic = 0 then                   put "Unable to load JPG: ", Error.LastMsg                   return                   end if                      Pic.Draw (pic, 200, 400, picMerge)                   Music.PlayFile("boo.wav")                              delay (2000)                   cls                   pic:= Pic.FileNew ("quizbackground2.jpg")                   if pic = 0 then                   put "Unable to load JPG: ", Error.LastMsg                   return                   end if                      Pic.Draw (pic, 0, 0, picCopy)                                    tmp := Rand.Int(0, 5)                   Pic.Draw(q(tmp), 300, 200, picMerge)               end if                         exit when x >= 300 and x <= 510 and y >= 200 and y <= 250             end loop             if x >= 300 and x <= 510 and y >= 200 and y <= 250 then                 cls                 pic:= Pic.FileNew ("quizbackground2.jpg")                 if pic = 0 then                 put "Unable to load JPG: ", Error.LastMsg                 return                 end if                    Pic.Draw (pic, 0, 0, picCopy)                  tmp := Rand.Int(1, 5)                 Pic.Draw(q(tmp), 300, 200, picMerge)             end if     end if         if tmp = 1 then         Draw.Box (310, 270, 625, 330, black)         loop            Pic.Draw(q(1), 300, 200, picMerge)            buttonwait ("down", x, y, bnum, bud)            cls            if not (x >= 310 and x <= 625 and y >= 270 and y <= 330) then                pic:= Pic.FileNew ("quizbackground2.jpg")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 0, 0, picCopy)                         pic:= Pic.FileNew ("hintq4.bmp")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 200, 400, picMerge)                Music.PlayFile("boo.wav")                           delay (2000)                cls            end if                      exit when x >= 310 and x <= 625 and y >= 270 and y <= 330          end loop             if x >= 310 and x <= 625 and y >= 270 and y <= 330 then                 cls                 pic:= Pic.FileNew ("quizbackground2.jpg")                 if pic = 0 then                 put "Unable to load JPG: ", Error.LastMsg                 return                 end if                    Pic.Draw (pic, 0, 0, picCopy)                 tmp := Rand.Int(2, 5)                 Pic.Draw(q(tmp), 300, 200, picMerge)             end if              end if         if tmp = 2 then         Draw.Box (300, 350, 770, 400, black)         loop            Pic.Draw(q(2), 300, 200, picMerge)            buttonwait ("down", x, y, bnum, bud)            cls            if not (x >= 300 and x <= 770 and y >= 350 and y <= 400) then                pic:= Pic.FileNew ("quizbackground2.jpg")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 0, 0, picCopy)                         pic:= Pic.FileNew ("hintq6.bmp")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 200, 400, picMerge)                Music.PlayFile("boo.wav")                           delay (2000)                cls                pic:= Pic.FileNew ("quizbackground2.jpg")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 0, 0, picCopy)                           end if                    exit when x >= 300 and x <= 770 and y >= 350 and y <= 400        end loop             if x >= 300 and x <= 770 and y >= 350 and y <= 400 then                 cls                 pic:= Pic.FileNew ("quizbackground2.jpg")                 if pic = 0 then                 put "Unable to load JPG: ", Error.LastMsg                 return                 end if                    Pic.Draw (pic, 0, 0, picCopy)                  tmp := Rand.Int(3, 5)                 Pic.Draw(q(tmp), 300, 200, picMerge)             end if                end if         if tmp = 3 then         Draw.Box (280, 420, 700, 470, black)         loop            Pic.Draw(q(3), 300, 200, picMerge)            buttonwait ("down", x, y, bnum, bud)            cls            if not (x >= 280 and x <= 700 and y >= 420 and y <= 470) then                pic:= Pic.FileNew ("quizbackground2.jpg")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 0, 0, picCopy)                         pic:= Pic.FileNew ("hintq7.bmp")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 200, 400, picMerge)                Music.PlayFile("boo.wav")                           delay (2000)                cls                pic:= Pic.FileNew ("quizbackground2.jpg")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 0, 0, picCopy)                           end if                      exit when x >= 280 and x <= 700 and y >= 420 and y <= 470          end loop             if x >= 280 and x <= 700 and y >= 420 and y <= 470 then                 cls                 pic:= Pic.FileNew ("quizbackground2.jpg")                 if pic = 0 then                 put "Unable to load JPG: ", Error.LastMsg                 return                 end if                    Pic.Draw (pic, 0, 0, picCopy)                  tmp := Rand.Int(4, 5)                 Pic.Draw(q(tmp), 300, 200, picMerge)             end if              end if     if tmp = 4 then         Draw.Box (300, 350, 720, 400, black)         loop            Pic.Draw(q(4), 300, 200, picMerge)            buttonwait ("down", x, y, bnum, bud)            cls            if not (x >= 300 and x <= 720 and y >= 350 and y <= 400) then                pic:= Pic.FileNew ("quizbackground2.jpg")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 0, 0, picCopy)                         pic:= Pic.FileNew ("hintq8.bmp")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 200, 400, picMerge)                Music.PlayFile("boo.wav")                           delay (2000)                cls                pic:= Pic.FileNew ("quizbackground2.jpg")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 0, 0, picCopy)                           end if                      exit when x >= 300 and x <= 720 and y >= 350 and y <= 400          end loop             if x >= 300 and x <= 720 and y >= 350 and y <= 400 then                 cls                 pic:= Pic.FileNew ("quizbackground2.jpg")                 if pic = 0 then                 put "Unable to load JPG: ", Error.LastMsg                 return                 end if                    Pic.Draw (pic, 0, 0, picCopy)                 tmp := Rand.Int(5, 5)                 Pic.Draw(q(tmp), 300, 200, picMerge)             end if                    end if     if tmp = 5 then      Draw.Box (285, 200, 540, 250, black)         loop            Pic.Draw(q(5), 300, 200, picMerge)            buttonwait ("down", x, y, bnum, bud)            cls            if not (x >= 285 and x <= 540 and y >= 200 and y <= 250) then                pic:= Pic.FileNew ("quizbackground2.jpg")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 0, 0, picCopy)                         pic:= Pic.FileNew ("hintq9.bmp")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 200, 400, picMerge)                Music.PlayFile("boo.wav")                           delay (2000)                cls                pic:= Pic.FileNew ("quizbackground2.jpg")                if pic = 0 then                put "Unable to load JPG: ", Error.LastMsg                return                end if                   Pic.Draw (pic, 0, 0, picCopy)                           end if                      exit when x >= 285 and x <= 540 and y >= 200 and y <= 250          end loop             if x >= 285 and x <= 540 and y >= 200 and y <= 250 then                 cls                 pic:= Pic.FileNew ("quizbackground2.jpg")                 if pic = 0 then                 put "Unable to load JPG: ", Error.LastMsg                 return                 end if                    Pic.Draw (pic, 0, 0, picCopy)                      tmp := Rand.Int(0, 5)                 Pic.Draw(q(tmp), 300, 200, picMerge)             end if         end if         end loop

Please specify what version of Turing you are using
I'm using Turing 4.0.3 (the only version my school provided)

[Kharybdis]

Well, to prevent a number from reoccurring, you can just randomize the order itself in the beginning, and use a loop with that new order. To calculate the score on a quiz, if the person gets it right, you assign + 1 to a counting variable. If a person gets it wrong, you assign the counting variable -1.

Turing:

var count := 0 if right then count +=1 elsif wrong then count -=1 end if

I don't quite see a way for the user to respond to your program, but i did glance over it just briefly. One way to exit your program would be to have the whole program in a loop that ends when 5 questions have been asked or when the user types a letter or any other input that symbolizes an exit command, at which point the program exits.

[TerranceN]

I would reccomend you make an array of boolean values, the same size as your questions array, so that when you ask a question you can mark that you have already done that question. Then you can put your random number assignment in a loop and only exit when the number has not already been asked (just make sure to also have a way to check when all of the questions have been asked). For the score, that is just a global number that you increment when someone gets a right answer.

[Insectoid]

That's way too complicated TerranceN. A better way is to have an array and select 2 random elements and swap them, then do it again, and again, and again, until it's nicely shuffled, then ask in that order.

[TerranceN]

I know it's not the most efficient way, but it was what I used when I was learning turing, and since Wintermini's code is pretty much brute forcing through the problem, I figured a conceptually simple answer (at least it seems that way to me) that is inefficient would be better/more helpful then an answer that requires more thinking and is more efficient.

That raises a good question, though, is it better to teach the 'most efficient answer', or teach the basic answer, and let students figure out better answers on their own? I have learned through the second way, so thats probably why I default to it.

I'm running on low sleep, so I'm sorry if that makes no sense.

[DemonWasp]

In general, one hopes to educate the student by providing first a simple, direct approach, then a faster approach. In some cases, the two are the same.

In this particular case, both have reasonable analogies. TerranceN's method is equivalent to writing down the numbers 1 to N, then crossing off the ones that you randomly generate. If a number is already crossed off, you reroll. insectoid's method is akin to shuffling a deck of cards and drawing from the top, discarding cards as you go - you'll never get the same card (or number) twice.

[Ktomislav]

I think this is the best way to go:
Random a number from one to the number of questions.
Write the question, user input and that stuff.
Swap the last question and the question you have just randomed.
Decrease the number of questions.