Program:

The source code to find the sum of the right diagonal of the matrix is given below. The given program is compiled and executed successfully on Microsoft Visual Studio.

//C# program to find the sum of each column of the matrix.

using System;

class MatrixDemo
{
    public static void Main(string[] args)
    {
        int i   = 0;
        int j   = 0;

        int sum = 0;
        int row = 2;
        int col = 2;
        
        int[,] Matrix = new int[row, col];
        
        Console.Write("Enter the elements of matrix: ");
        for (i = 0; i < row; i++)
        {
            for (j = 0; j < col; j++)
            {
                Matrix[i, j] = int.Parse(Console.ReadLine());
            }
        }

        Console.WriteLine("\nMatrix: ");
        for (i = 0; i < row; i++)
        {
            for (j = 0; j < col; j++)
            {
                Console.Write(Matrix[i, j] + "\t");
            }
            Console.WriteLine();
        }

        for (i = 0; i < row; i++)
        {
            sum = 0;
            for (j = 0; j < col; j++)
            {
                sum += Matrix[j, i];
            }
            Console.WriteLine("Sum of column[{0}]: {1}", (i + 1), sum);
        }
    }
}

Output:

Enter the elements of matrix: 1
2
3
4
5
6
7
8
9

Matrix:
1       2       3
4       5       6
7       8       9
Sum of right diagonal is: 15
Press any key to continue . . .

Explanation:

In the above program, we created a class MatrixDemo that contains a Main() method. The Main() method is the entry point for the program, Here, we created a 2-D array to represent a matrix.

Console.Write("Enter the elements of matrix: ");
for (i = 0; i < row; i++)
{
    for (j = 0; j < col; j++)
    {
        Matrix[i, j] = int.Parse(Console.ReadLine());
    }
}
Console.WriteLine("\nMatrix: ");
for (i = 0; i < row; i++)
{
    for (j = 0; j < col; j++)
    {
        Console.Write(Matrix[i, j] + "\t");
    }
    Console.WriteLine();
}

In the above code, we read the elements of the matrix and print the matrix on the console screen.

for (i = 0; i < row; i++)
{
    for (j = 0; j < col; j++)
    {
        if(i==j)
            sumRightDiagonal += Matrix[j, i];
    }
}

Here, we calculated the sum of the right diagonal of the matrix and then print that on the console screen.