I have random numbers such as

1 6 8 5 7 3 9 2 4

in a 1 dimensional array

what for loop do I use to reorder the numbers from 1 through 9?

thanks.

Jump to PostWhy wouldn't you just assign the array members 1-9?

`int i, array[9]; for (i = 0; i < 9; ++i) { array[i] = i + 1; }`

Jump to PostYou need a bubble sort algo.

You need to compare the first number to the second, and swap accordingly.

or...what you could do, which would be a lot easier

assign a temp array of the same size,

run a loop to find the smallest number

plop the …

Jump to Post>You need a bubble sort algo.

Please don't suggest bubble sort if other options are available.

Dave Sinkula
2,398
long time no c
Team Colleague

Why wouldn't you just assign the array members 1-9?

```
int i, array[9];
for (i = 0; i < 9; ++i)
{
array[i] = i + 1;
}
```

Gnome_101
0
Light Poster

You need a bubble sort algo.

You need to compare the first number to the second, and swap accordingly.

or...what you could do, which would be a lot easier

assign a temp array of the same size,

run a loop to find the smallest number

plop the result in the first element of the second array

set the value u just moves in the first array to zero

run the loop 9 time.

:)

Narue
5,707
Bad Cop
Team Colleague

>You need a bubble sort algo.

Please don't suggest bubble sort if other options are available.

vegaseat
1,735
DaniWeb's Hypocrite
Team Colleague

How about a shell-sort, this one has three nested for loops ...

```
// shell sort routine of n items in array[n]
void shellsort(int *array, int n)
{
int basectr, curctr, gapctr, gap, temp;
// reduce gap by 1/2 each loop
for(gap = n / 2; gap > 0; gap /= 2)
{
for(basectr = gap; basectr < n; basectr++)
{
for(curctr = basectr - gap; curctr >= 0; curctr -= gap)
{
gapctr = curctr + gap;
if (array[curctr] > array[gapctr])
{
temp = array[curctr];
array[curctr] = array[gapctr];
array[gapctr] = temp;
}
else break;
}
}
}
}
```

Gnome_101
0
Light Poster

>You need a bubble sort algo.

Please don't suggest bubble sort if other options are available.

Why? Learning a bubble sort is a good practice for learning C with arrays, and the such.

:rolleyes:

Narue
5,707
Bad Cop
Team Colleague

Because bubble sort is one of the worst sorting algorithms invented, promotes bad habits, and any of the other quadratic sorts are equally good practice. I personally believe that bubble sort should only be used as an example of how **not** to sort data.

Gnome_101
0
Light Poster

Because bubble sort is one of the worst sorting algorithms invented, promotes bad habits, and any of the other quadratic sorts are equally good practice. I personally believe that bubble sort should only be used as an example of hownotto sort data.

That is a good response, and as such, an understandble way of looking at a bad algo for getting the job done.

Sadly though, it is still taught, and without your explination as to why not to suggest this algo, was a little put off(your first post). As a comp sci student who has had years of C++ experience, it seemed like a smart way to start learning sorting. Is the speed of the algo is in question, or just he methodology? Time for sorting with numbers under the curve of the function for the algo (which I believe this appilcation would have been ok for) are minimal. We are talking milliseconds. understandbly when the dataset moves into the range of millions, there are other methods to improve overall performace time. As for the implementaton, I tend to agree with you as it tends messy.

Now that I can understand where you are coming from, I won't suggest it again.

Gnome

hopeolicious
0
Light Poster

Narue
5,707
Bad Cop
Team Colleague

>Sadly though, it is still taught

Indeed.

>Is the speed of the algo is in question

Yes, always. Bubble sort (as taught) does a lot of unnecessary work. It can be improved slightly, but that's almost always left as an exercise.

>understandbly when the dataset moves into the range of millions

Thousands. Bubble sort's growth is such that even sorting 10,000 records could be noticeably slow (less than that if the records are non-trivial). If you have millions of records then a suitable data structure or an nlogn sort would be more appropriate. The quadratic sorts are only useful for small data sets, or as components in implementing a more sophisticated algorithm.

>how can you reorder numbers that are user input using selection sort in a 1 dimension array and output each element

You've asked this same question four times if I recall correctly. I also recall answering it fully, with code examples. What's the problem?

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