HW7.2

 1 import java.util.Scanner;
 2 
 3 public class Solution
 4 {
 5     public static void main(String[] args)
 6     {
 7         Scanner input = new Scanner(System.in);
 8         int[][] matrix = new int[4][4];
 9         System.out.println("Enter a 4-by-4 matrix row by row: ");
10         for(int i = 0; i < 4; i++)
11             for(int j = 0; j < 4; j++)
12                 matrix[i][j] = input.nextInt();
13 
14         input.close();
15 
16         System.out.println("Sum of the elements in the major diagonal is " + sumMajorDiagonal(matrix));
17     }
18 
19     public static int sumMajorDiagonal(int[][] m)
20     {
21         int sum = 0;
22         for(int i = 0; i < 4; i++)
23             sum += m[i][i];
24         return sum;
25     }
26 }