Deleting duplicates in the array

Question

I made a program to delete duplicates in an array but the program\'s if condition always remain true. I understood what the problem was,changed arr[i] to arr[count] and allocate

Answer 1

You never initialized arr. Currently it's just a pointer, it has no actual bound on it, so you could be overwriting something else.

Also, you're never incrementing scanf("%d",&arr[i]); I think you want that to read scanf("%d",&arr[counter]);

Answer 2

To remove duplicates from array create a method, that:

• sorts the array
• counts unique values
• creates a new array, that is of size unique values
• start coping from 1 array to the other, when their values are different

To use quicksort in c, you need comparator function like:

int comp(const void *x, const void *y) {
  return (*(int*)x - *(int*)y);
}

And then you can call it with:

qsort(array, 10, sizeof(int), comp);

To count unique items in sorted array, iterate over the array, and do something like:

if(sortedarray[i]!=sortedarray[i+1]) count++;