C++ coding:Quick Sort

#include <iostream.h>
#include <stdio.h>

class List
{
   
    public:
        int arr[20];    //Array of integers to hold values
        int cmp_count; //Number of comparisons
        int mov_count; //Number of data movements
   
        int n; // Number of elements in the array

        List()
        {
            cmp_count = 0;
            mov_count = 0;
        }

void read()
{
// Get the number of elements to store in the array
while (true)
{
cout << "\nEnter the number of elements in the array: ";
cin >> n;
if (n <= 20)
break;
else
cout << "\nArray can have maximum 20 elements.\n";
}

cout << "\n-----------------------\n";
cout << " Enter array elements  \n";
cout << "-----------------------\n";
     
// Get array elements
for (int i = 0; i < n; i++)
{
cout << "<" << (i + 1) << "> ";
cin >> arr[i];
}
}

void swap(int x, int y) //Swaps the element at index x with the element at index y
        {
            int temp;
            temp = arr[x];
            arr[x] = arr[y];
            arr[y] = temp;
        }
   
        void q_sort(int low, int high)
        {
            int pivot, i, j;
            if (low > high)
                return;
       
            //Partition the list into two parts:
            //One containing elements less than or equal to pivot
            //Other containing elements greater than pivot
       
            i = low+1;
            j = high;
       
            pivot = arr[low];
       
            while (i <= j)
            {
                //Search for an element greater than pivot
                while ((arr[i] <= pivot) && (i <= high))
                {
                    i++;
cmp_count++;
                }

cmp_count++;
           
                //Search for an element less than or equal to pivot

                while ((arr[j] > pivot) && (j >= low))
                {
                    j--;
cmp_count++;
                }
cmp_count++;
           
                if (i < j)  //If the greater element is on the
                            //left of the smaller element
                {
                    //Swap the element at index i with the element at index j
                    swap(i, j);
mov_count++;
                }
            }
       
            //j now contains the index of the last element in the sorted list.
       
            if (low < j)
{
                swap(low,j);    //Move the pivot to its correct position in the list
mov_count++;
            }
       
            //Sort the list on the left of pivot using quick sort
            q_sort(low, j - 1);
       
            //Sort the list on the right of pivot using quick sort
            q_sort(j + 1, high);
        }

void display()
{
cout << "\n-----------------------\n";
cout << " Sorted array elements \n";
cout << "-----------------------\n";
     
for (int j = 0; j < n; j++)
{
cout << arr[j] << endl;
}
     
cout << "\nNumber of comparisons: " << cmp_count;
cout << "\nNumber of data movements: " << mov_count;
}

int getSize()
{
return (n);
}
};


void main()
{
// Declaring the object of the class
        List myList;
       
// Accept array elements
myList.read();
 
        // Calling the sorting function
        myList.q_sort(0, myList.getSize() - 1);  // First call to Quick Sort Algorithm
       
        // Display sorted array
myList.display();
}