import java.util.Scanner; public class Solution { public static void main(String[] args) { Scanner input = new Scanner(System.in); int[][] matrix = new int[4][4]; System.out.println("Enter a 4-by-4 matrix row by row: "); for(int i = 0; i < 4; i++) for(int j = 0; j < 4; j++) matrix[i][j] = input.nextInt(); input.close(); System.out.println("Sum of the elements in the major diagonal is " + sumMajorDiagonal(matrix)); } public static int sumMajorDiagonal(int[][] m) { int sum = 0; for(int i = 0; i < 4; i++) sum += m[i][i]; return sum; } }