"Jimakos Bilakis" <divasila238@yahoo.gr> wrote in message
news:1143133472.952475.134110@g10g2000cwb.googlegr oups.com...[color=blue]
> Hi everyone!
>
> I want to create a function that it will take as parameters a table
> (float), an integer (the number of Table's rows) and it will re-arrange
> the elements in the table from the smallest value to the biggest one. I
> know it's very simple but something is missing from my code... Untill
> now i manage to create something like this:
>
> 1. void FunctionReArrange (float Table[], int TableRows)
> 2. {
> 3. float Help1 = 0;
> 4. float Help2 = 0;
> 5.
> 6. if (TableRows <= 1)
> 7. cout<<"Nothing's gonna happen!";
> 8. else
> 9. {
> 10. for (int a=0; a<=TableRows-1; a++)[/color]
You should terminate with : "a < TableRows-1" (or "a <= TableRows-2"), so
that the final iteration in the loop below doesn't hit the same location,
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> 11. {
> 12. for (int b=1; b<=TableRows-1; b++)
> 13. {
> 14. if (Table[a] > Table[b])
> 15. {
> 16. Help1 = Table[a];
> 17. Help2 = Table[b];
> 18.
> 19. Table[a] = Help2;
> 20. Table[b] = Help1;[/color]
simpler:
{
float tmp = Table[a];
Table[a] = Table[b];
Table[b] = tmp;
}
(or, I think there's a std::swap function which also does the trick!)
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> 21. }
> 22. }
> 23. }
> 24. }
> 25.}
>
> I tried this one with the table (in main):
>
> float myTable[4] = {1.17, 1.37, 1.00, 1.31};
> FunctionReArrange (myTable, 4);
>
> When i compile and run the code, i get results similar to these:
> myTable = {1.00, 1.37, 1.17, 1.31} which of course aren't the right
> results! (1.00, 1.17, 1.31, 1.37) It's very clear that i cannot see a
> detail... The error is somewhere in lines 14 - 20.
>
> When it comes to line 12 for the 1st time it has
> Table[a] = Table[0] = 1.17 and Table[b] = Table[1] = 1.37. It's ok so
> it takes the next element.
> Then it has
> Table[a] = Table[0] = 1.17 and Table[b] = Table[2] = 1.00.
> So it goes for the change. After that i have myTable[4] = {1.00, 1.37,
> 1.17, 1.31}![/color]
That's correct. All you're interested in after the first iteration of the
outer loop is: what is the first value in the array. It should be 1.00.
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> Here is the "spot" where i want to write something so i can return the
> whole procedure from the beginning, couse my code continues like no
> change happened.(It continues the check like i had declared the table
> myTable with elements {1.00, 1.37, 1.17, 1.31} from the start - it
> doesn't recognise that the elements have changed and that it has to
> beggin the procudure from the beginning)!
>[/color]
You don't need to restart from the beginning.
This sort is referred to as a "bubble sort". One values "bubbles up" to its
correct location after each iteration of the outer loop.
After the first complete iteration of the outer loop (i.e., after the inner
loop has completed going through all elements the first time, when a is 0),
the first element of the array will be the smallest value (1.00). The
second complete iteration of the loop (where a is 1) will result in the
second smallest element being in the second position, so that the array will
start out {1.00,1.17,...}. What comes after those values in the array isn't
really relevant (yet). So...after each complete iteration of the outer
loop, one more value will have "bubbled up" to where it belongs in the list.
I don't see the problem here offhand, but try my fix I mention above, and
try outputting the values (using std::cout) at the bottom of the outer (a)
for loop. Then see if you don't get the resulyts I describe.
-Howard
