Generate random numbers, no duplicates.

[renegod]

I am taking MDM4U and I am suppose to analyze "probability game".
The game i choose is a variant of bingo.

I need to generate 90 numbers (between 1 .. 90), no duplicates.
Then generate 15 numbers between (1 .. 90, no duplicates. <- got to do that 5 times (players)

After that I will run my procedure which will see which player won.

I got everything down pretty well, except I cant seem to figure out how to generate random numbers with no dupes,

can anyone help, I dont necessarily need the whole program done for me, a flow chart, or some detail instructions and I could do the rest.

[Clayton]

Have an array with 90 elements, each holding a value from 1 - 90. Then take a random element, record it's value, and then remove that element from the list. Rinse, lather and repeat until the desired consistency.

[renegod]

Well i was late on reading your reply, but I was able to get it on my own, thank you for the help, but i do not understand what you mean by

"Have an array with 90 elements, each holding a value from 1 - 90. Then take a random element, record it's value, and then remove that element from the list. Rinse, lather and repeat until the desired consistency."
what list?


also heres my code:

Quote:

%program name: random number generator, no dupes
%programer: shpetim salihu

var rint : int := 0 % the randomly generated number
var r90 : array 1 .. 90 of int % the array where all the nubers go (the bingo list)
var yn : int := 0 % was the number a duplicate? yes/no
var sentinel : int := 0 %exit variable for the loop

for a : 1 .. 90 %sets the r90 variable to 0
r90 (a) := 0
end for

for g : 1 .. 90 % main for loop, runs 90 times, g = generate

sentinel := 0 %reset the sentinel value

loop %this loops until a random number that is not a duplicate is generated
exit when sentinel = 1%exit statement
yn := 0 %resets the "was it a dupe, yes/no" value
randint (rint, 1, 90)%generates a random number

for g2 : 1 .. g % loop to check if the number is duplicate
exit when yn = 1 %if it is dupe, it will exit

if rint = r90 (g2) then % is it a dupe?
yn := 1 %
else
yn := 0 %

end if
end for

if yn = 0 then %if its not a dupe, it wil add it to the array
r90 (g) := rint
sentinel := 1 %set the sentinel so that it exits
else
end if
end loop

put " ", r90 (g) .. %displays numbers for the user
end for

[zylum]

You can have an array of consisting of the numbers 1..90 and shuffle the array. Then you iterate through the array to generate the next random number.

[Clayton]

The list is your array. Although, thinking about it now, zylum's is an excellent way of doing it as well.

[Tony]

Clayton - you are effectively shuffling the array just the same. Though you are discarding the element at read, rather than keeping it in the memory and advancing the index.

[Nick]

I think zylum's way is more efficient though :/ and I never thought of doing it that way

that will help with the card game I'm making!

[zylum]

My method is just easier for Turing as you wont have to create a list to use it

[Tony]

Clayton's implementation would be something like this:

Turing:

var nums : array 1 .. 90 of int var k : int for i: 1 .. 90    nums[i] := i end for for decreasing j: 90 .. 1    k := Rand.Int(1, j)  % get random element    put nums[k]  % result    nums[k] := nums[j]  % remove element end for

@zylum - it's not trivial to shuffle in Turing and will require an extra loop.

[Nick]

Tony wouldn't that implemtation have duplicate values?

[Tony]

how so? Once the random element k is printed to screen, it's taken out of the list and replaced with another element, not previously picked (well... unless it's replaced with itself).

[renegod]

Tony @ Wed Jan 09, 2008 1:29 pm wrote:

Clayton's implementation would be something like this:

Turing:

var nums : array 1 .. 90 of int var k : int for i: 1 .. 90    nums[i] := i end for for decreasing j: 90 .. 1    k := Rand.Int(1, j)  % get random element    put nums[k]  % result    nums[k] := nums[j]  % remove element end for

@zylum - it's not trivial to shuffle in Turing and will require an extra loop.

wow thats impressive. much better than mine.
thanks for all the help guys.

[Nick]

oh I see lol that however won't work for the card game I'm making :/ oh well I already wrote up my shuffling script

[sh0td0wn]

hmmm... I'm trying to use the solution provided in the second to be implemented in my Quiz game but no avail... It doesn't stop and there is still duplicates.

The one I did before I saw this was a loop with randint with an if statement that if it generates this number... a question will be asked and a counter will increase. If the counter will reach 10 Qs, the loop will stop.

My problem is the duplicates.