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Could you post the relevant code, please?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
modified on Wednesday, November 24, 2010 8:24 AM
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Hello Sir
I got the HAndle of tht ListBox in Lbutton Down.
Thanks for ur precious time .
Regards
Yogesh
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Hi,
I pass two input string from VBA(forms) to (Vc++)DLL. This vc++ DLL is concatinate the string and return to VBA Forms.
please any sample code or idea?
Regards,
M.mathivanan
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Unless you are doing some other string manipulation other than just concatenating two strings, why don't you just concatenate them within the VB app?
It was broke, so I fixed it.
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I agree, Excel had its own C compiler so even for speed advantages I cant see the point of calling to vc++ to concatenate two strings! If it was another datatype that would be a different story.
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Hi all,
I have a working program that reads stocks symbols and values from a text file and do some operations on the data, and then it outputs the the data as two reports. The first report is sorted by stock symbols, and the other report is sorted by percent gain/loss.
I'm having difficulties understating how these sort functions are doing the comparisons..
Can you guys provide some explanation please?
template<class elemType>
void listType<elemType>::sort(){
int i, j;
int min;
elemType temp;
for (i = 0; i <length; i++){
min = i;
for (j = i + 1; j < length; ++j)
if (list[j] < list[min])
min = j;
temp = list[i];
list[i] = list[min];
list[min] = temp;
}
}
void stockListType::sortByGain(){
int i, j;
int temp;
indexByGain = new int[length];
for(int c = 0; c < length; c++){
indexByGain[c] = c;
}
for (i = 0; i <length; i++){
for (j = i + 1; j < length; j++){
if (list[indexByGain[j]].getPercentChange() > list[indexByGain[i]].getPercentChange()){
temp = indexByGain[i];
indexByGain[i] = indexByGain[j];
indexByGain[j] = temp;
}
}
}
}
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The algorithm is something like this -
1. Take the first element in the array.
2. Compare with the rest of the elements below it to check if there is a lesser value.
3. If there is a lesser value, swap the elements.
4. Take the next element in the array.
5. Go to step 2.
The std::sort function would be more efficient if you can use it.
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Babylon Lion wrote: Can you guys provide some explanation please?
See here.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
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thank you 
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I may have gone mad but this is a selection sort surely...
Edit: my hesitation is due to the fact that (as pointed out above) you never see these sorts of sorts in the wild because there are much better sorts of sorts.
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As already suggested, that's the famous bubble sort (the most intuitive one: lower elements comes up).
You may notice that
for (i = 0; i < length; i++)
could be replaced by
for (i = 0; i < length-1; i++)
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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So whenever a comparison like that is required, a bubble function is used, right?
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There's no bubble function, actually. From Wikipedia[^] : "The algorithm gets its name from the way smaller elements 'bubble' to the top of the list".
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Babylon Lion wrote: whenever a comparison like that is required, a bubble function is used, right?
The bubble sort is not the most efficient method of sorting data as there is a lot of swapping going on. In a short list (array) it works fine and is quicker and easier to code. With a shorter list there really isn't too much loss of efficiency.
This site provides a good visual demonstration of the different types of sorts http://www.sorting-algorithms.com/[^]
As Superman states use the std::sort function if you can, although learning sort algorithms can be useful.
Good luck!
It was broke, so I fixed it.
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QuickSort is infinitely faster than a bubble sort. I use it exclusively. It recursively breaks the list up into smaller and smaller pieces. The resulting time-to-sort relative to the length of the list is linear instead of exponential.
Found this from Googling QUICKSORT.
There are many other sources of info out there.
void swap(int *x,int *y)
{
int temp;
temp = *x;
*x = *y;
*y = temp;
}
int choose_pivot(int i,int j )
{
return((i+j) /2);
}
void quicksort(int list[],int m,int n)
{
int key,i,j,k;
if( m < n)
{
k = choose_pivot(m,n);
swap(&list[m],&list[k]);
key = list[m];
i = m+1;
j = n;
while(i <= j)
{
while((i <= n) && (list[i] <= key))
i++;
while((j >= m) && (list[j] > key))
j--;
if( i < j)
swap(&list[i],&list[j]);
}
swap(&list[m],&list[j]);
quicksort(list,m,j-1);
quicksort(list,j+1,n);
}
}
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danataylor wrote: QuickSort is infinitely faster than a bubble sort
In general it is; but in its worse case, it's as bad as other sorts.
Watched code never compiles.
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QuickSort isn't "infinitely" faster than a bubble sort. Its efficiency depends on the choice of pivot, and its performance can be sensitive to the initial order (as explained in that article). For small arrays a bubble sort can be faster!
It's usually better to use a built-in sort because that will have had time spent on it to reduce such problems.
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I would recommend the use of the functions from the standard library like qsort or qsort_s.
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«_Superman_» wrote: I would recommend the use of the functions from the standard library like qsort or qsort_s.
agreed! save time
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You
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Interesting sort functions. The first function can be associated to a "bubble sort" except nothing is "bubbling up" in the list array. The inner loop is only storing the index of the smallest value. Then at the end of the second loop (bottom of the first loop), the values are swapped. This is more efficient than a bubble sort because we are not swapping the items in the array (excessive memory access) every time we determine that (list[j] < list[min]). The swap is done n times rather than (n * n) times.
The second sort is sorting an array of indexes based on the percentage change. The original list array is untouched. It is used only for reference. The final result is the indexByGain array. This should be returned. But, it is not and so is lost. For the reporting, the programmer would need to run through the indexByGain to print out the report as:
for (int k = 0; k < length; k++)
printf("%f\n", list[indexByGain[k]].getPercentChange());
assuming that getPercentChange() returns a double or float. Sorry, my C coding is a bit rusty.
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Array.Sort and ArrayList.Sort are both Quick Sorts. Can you create either of these with your data and use them?
"Coding for fun and profit ... mostly fun"
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The first one (sort()), scans the list to find the smallest item (it assumes that elemType has operator<() defined, which we presume is bases on it's ticker symbol string). It then swaps that items with the item in list[0]. Next it scans for the smallest between list[1] and the end, and swaps that with list[1], and onward, swapping the smallest among list[2] & the end with list[2]. I believe this actually makes it an insertion sort, which is slightly faster that a bubble sort (and generally considered the best for small lists)
The second sort (sortByGain()) doesn't want to change the order of the items in list (which presumably have just been sorted by sort()), so it creates a array of indexes into list, so that after both functions are called list[0] is the first stock alphabetically, while list[indexByGain[0]] is the stock with the highest gain.
sortByGain() does a proper (slow) Bubble sort, potenially swapping after every compare, moving the desired item (which is the smallest in the first sort and the largest in the second) one position closer to it's final location each time.
Truth,
James
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Hello,
Im using a bunch of owner-drawn button in an MFC application Im updating. Im loking for an easy way to keep the buttons down when selected and implimenting ToolTip. Ive looked everywhere I can think of and cant find a solution.
Thanks in advanced
Derrek
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