I am trying my sorting method, which works well with data with no repeates entries, but am getting random numbers in place of repeated numbers? - c++

Question

I have been trying a sorting method in which I subtract each number stored in an array by other elements in the same array. Then, I saw a pattern that the number of differences which come to be negative, is the rank or position of element in the Sorted one. But, things go wrong when I am using repeated entries.
My basic method is :
Take every element of the SampleArray.
subtract it from every element of the SampleArray
check if the difference comes to be negative.
if it is then, increase a variable called counter.
And use this counter as the position of element in sorted array.
For example: lets take (5,2,6,4)
first take 5, subtract it from each of the numbers which will give results (0,-3,1,-1), so counter will become 2, which will be the index of 5 in the sorted Array. And repeat it for each of the elements.
for 5, counter will be 2.
for 2, counter will be 0.
for 6, counter will be 3.
for 4, counter will be 1.
And hence the sorted Array will be {2,4,5,6}.
First, see the code :
#include <iostream>
using namespace std;
void sorting(int myArray[], int sizeofArray);
int main()
{
int checkArray[] = {5,4,2,20,12,13,8,6,10,15,0}; //my sample Arry
int sized;
sized=sizeof checkArray/sizeof(int);//to know the size
cout << sized << endl;
sorting(checkArray, sized);
}
void sorting(int myArray[], int sizeofArray)
{
int tempArray[sizeofArray];
for (int i=0; i<sizeofArray; i++)
{
int counter=0;
for (int j=0;j<sizeofArray; j++ )
{
int checkNum = myArray[j]-myArray[i];
if (checkNum<0)
counter++; //to know the numbers of negatives
else
counter+=0;
}
tempArray[counter]=myArray[i];
}
for (int x=0;x<sizeofArray; x++)
{
cout << tempArray[x] << " " ;
}
}
Now, if we run this program with entries with no repetitions then, it sorts out the array, But if we use repeated entries like
int checkArray[] = {8,2,4,4,6}
the tempArray gets its first element as 2 as counter will be zero.
the tempArray gets its second element as 4 as counter will be 1.
but, the tempArray can't get its third one as counter will be still 1, and thus prints some randomNo in place of this. (here the things go wrong).
Can you please suggest a method to solve this?

Answer 1

This is an odd way of writing insertion sort, https://en.wikipedia.org/wiki/Insertion_sort
I would assume you can change your condition to:
if (checkNum<0 || (checkNum==0 && j<i))
But I would suggest using a proper sorting routine instead
The idea is to separate duplicates by saying that if the values are the same we sort according to their order in the sequence; as if the sequence was a pair of the value and the sequence number (0, 1, 2, 3, 4, 5, ...).

Answer 2

The issue here is that for any 2 equally sized numbers the nested loop will return the same counter value. Thus for such a counter value tempArray[counter + 1] will never be initialized.
The way to solve this would be to maintain a vector<bool> denoting what each position had been written and write to the next valid position if that is the case.
But supporting a second vector is just going to make your O(n2) code slower. Consider using sort instead:
sort(begin(checkArray), end(checkArray))