Bubble Sort Problem

[gitoxa]

I came up with an idea to make a bubble sorter go faster. I read "comb sort" on wikipedia, and this came ot my head, even though comb sort is something else... heh.
Anyway, it's a bubble sort that goes both ways, up the array, then down, to lessen the time it takes to move small numbers from high indices to low ones. It works fine, until I try around 300 numbers. At some point, it just stops even though the numbers are not in order.

I've been staring at it for a while, with no solution becoming apparent. You guys see something I'm missing?

code:

%Swaps two numbers in an array. procedure Swap_Nums (var NumList : array 1 .. * of int, Temp1, Temp2 : int)     var Temp : int     Temp := NumList (Temp1)     NumList (Temp1) := NumList (Temp2)     NumList (Temp2) := Temp end Swap_Nums %Sorts an array of numbers, using the bubble sort method. procedure Bubble_Sort2_Nums (var NumList : array 1 .. * of int, NumNums : nat1)     var Done : boolean     var Temp : int     loop         Done := true         for Forward : 1 .. NumNums - 1             if NumList (Forward) > NumList (Forward + 1) then                 Swap_Nums (NumList, Forward, Forward + 1)                 Done := false             end if         end for         if ~Done then             Done := true             for decreasing Backward : NumNums .. 2                 if NumList (Backward) < NumList (Backward - 1) then                     Swap_Nums (NumList, Backward, Backward - 1)                     Done := false                 end if             end for         end if         exit when Done     end loop end Bubble_Sort2_Nums

code:

%Main const MAXNUMS := 300 var Numbers : array 1 .. MAXNUMS of int for Create : 1 .. MAXNUMS     randint (Numbers (Create), 1, 1000) end for Bubble_Sort2_Nums (Numbers, MAXNUMS) for Output : 1 .. MAXNUMS - 1     if Numbers(Output) > Numbers(Output+1) then         put "Fail"..     end if end for

[richcash]

Your NumNums parameter is declared as nat1.

nat1 is 1-byte so its range is 0-255. If you pass an argument that is greater than that it will basically be modulo-ed by 256 so your for loops will be incorrect. You should change the type of your parameter to support more bytes.

[gitoxa]

Oh, okay, thanks. Thought I'd gotten all the variables fixed.