remove duplicate element in an array

demonstrates an O(n²) method to remove the duplicated elements in an array

// caution: 1. don't try to return int[] array from a function, c++ doesn't support this, though c# does it well.
//              2. when passing an array to a function, also pass along the length, since in the scope of the function, the array is treated as point in the eye of compiler
//              3. when return a newly created array in the function, also return the lengh of the array, since you could only return a point
//              4. good luck!!!

#include "stdafx.h"
#include "windows.h"
#include "malloc.h"

int RemoveDuplicate(int* dupList, int ilenDupList, int** ppuniqueList);

int _tmain(int argc, _TCHAR* argv[])
{
 int dupList[] = {2, 3, 5, 7, 9, 10, 2, 5};
 int ilenDupList = sizeof(dupList) / sizeof(int);
 int* puniqueList;
 
 int ilenUniqueList = RemoveDuplicate(dupList, ilenDupList, &puniqueList);
 for(int i=0; i<ilenUniqueList; i++)
 {
  printf("%d ", puniqueList[i]);
 }
 return 0;
}

int RemoveDuplicate(int* dupList, int ilenDupList, int** ppuniqueList)
{
 if(dupList == NULL)
 {
  (*ppuniqueList) = NULL;
  return 0;
 }
 int* deletedMark = (int *)malloc( ilenDupList*sizeof(int) );
 ZeroMemory(deletedMark, ilenDupList*sizeof(int));
 //
 // Loop through to mark the duplicated elements in list: deletedMark
 //
 for(int i=0; i<ilenDupList; i++)
 {
  if( deletedMark[i]!=1 )
  {
   for(int j=i+1; j<ilenDupList; j++)
   {
    if(deletedMark[j]!=1)
    {
     if( dupList[i] == dupList[j] )
     {
      deletedMark[j] = 1;
     }
    }
   }
  }
 }

 //
 // Copy the unique element
 //
 // 1. measure the num of unique elem
 int inumUniqueElem = 0;
 for(int uniqueIndex=0; uniqueIndex<ilenDupList; uniqueIndex++)
 {
  if(deletedMark[uniqueIndex]!=1)
  {
   inumUniqueElem++;
  }
 }
 // 2. copy the unique elem to the result list
 int* puniqueList = (int*) malloc(inumUniqueElem*sizeof(int));
 int uniqueListIndex = 0;
 for(int dupListIndex=0; dupListIndex<ilenDupList; dupListIndex++)
 {
  if(deletedMark[dupListIndex]!=1)
  {
   puniqueList[uniqueListIndex++] = dupList[dupListIndex];
  }
 }
 (*ppuniqueList) = puniqueList;
 free(deletedMark);
 return inumUniqueElem;
}