Zadacha1-Function

#include <iostream>
#include <iomanip>

using namespace std;

void printMatrix(int a[], int n);

int main()
{
    const int SIZE = 10;
    int a[SIZE];
    int n;
    do
    {
        cout << "Enter n: ";
        cin >> n;
    }
    while (n < 4 || n > SIZE);

    cout << "Enter main diagonal sequence: ";
    for (int i = 0; i < n; i++)
    {
        cin >> a[i];
    }

    printMatrix(a, n);

    return 0;
}

void printMatrix(int a[], int n)
{
    double matrix[n][n];
    // main diagonal
    for (int i = 0; i < n; i++)
    {
        matrix[i][i] = a[i];
    }

    // below main diagonal
    for (int k = 1; k < n; k++)
    {
         for (int i = 0; i + k < n; i++)
         {
                            // row index + above element
            matrix[i + k][i] = i + k + matrix[i + k - 1][i];
         }
    }

    // above main diagonal
    for (int k = 1; k < n; k++)
    {
         for (int j = 0; j + k < n; j++)
         {
                                // below element     + left element
            matrix[j][j + k] = (matrix[j + 1][j + k] + matrix[j][j + k - 1]) / 2.0;
         }
    }

    // print matrix
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            cout << setw(5) << matrix[i][j] << " ";
        }
        cout << endl;
    }
}