#include<iostream>

using namespace std;
//function prototype
int SumDiagonal(int ** array2d, int array2dsize);

int main()
{
    //declare a pointer to a pointer (2d array)
    int **x;

    x = new int*[4]; //initialize as an pointer of size 4

    for(int i=0;i<4;i++)
            x[i] = new int[4];//initialize each 4 pointers to arrays (2d array created)

    cout<<"The array is\n";

    for(int i=0;i<4;i++)
    {   for(int j = 0;j<4;j++)
            {
            x[i][j] = j + 1;//put appropriate values
            cout<<x[i][j]<<" ";//output values
            }
        cout<<endl;
    }

    cout<<"The sum of the diagonal is:"<<SumDiagonal(x,4);//calculate sum



    return 0;//DONE
}

int SumDiagonal(int **array2d, int array2dsize)
    {
    int sum=0;//sum is zero

    for(int i=0;i<array2dsize;i++)
        sum+=array2d[i][i]; //add the diagonal elements (same index)

    return sum;//return the value
    }