Implement Merge Sort algorithm in C++

Code

// mergesort

#include <iostream>

using namespace std;

void merge(int arr[], int l, int m, int r)
{
    int i, j, k;
    int n1 = m - l + 1;
    int n2 = r - m;

    int L[n1], R[n2];

    for (i = 0; i < n1; i++)
    {
        L[i] = arr[l + i];
    }
    for (j = 0; j < n2; j++)
    {
        R[j] = arr[m + 1 + j];
    }

    i = 0;
    j = 0;
    k = l;
    while (i < n1 && j < n2)
    {
        if (L[i] <= R[j])
        {
            arr[k] = L[i];
            i++;
        }
        else
        {
            arr[k] = R[j];
            j++;
        }
        k++;
    }

    while (i < n1)
    {
        arr[k] = L[i];
        i++;
        k++;
    }

    while (j < n2)
    {
        arr[k] = R[j];
        j++;
        k++;
    }
}

void mergeSort(int arr[], int l, int r)
{
    if (l < r)
    {
        int m = l + (r - l) / 2;

        mergeSort(arr, l, m);
        mergeSort(arr, m + 1, r);

        merge(arr, l, m, r);
    }
}

int main()
{
    int n, i, j, temp;
    int arr[50];
    cout << "Enter the size of array: ";
    cin >> n;
    cout << "Enter the elements of array: " << endl;
    for (i = 0; i < n; i++)
    {
        cin >> arr[i];
    }
    mergeSort(arr, 0, n - 1);
    cout << "Sorted array: ";
    for (i = 0; i < n; i++)
    {
        cout << arr[i] << " ";
    }

    cout << endl;
    return 0;
}


Output

Enter the size of array: 6
Enter the elements of array: 
13
46
23
14
56
32
Sorted array: 13 14 23 32 46 56