ICSE Computer Applications important questions for 2027, unit by unit.

int a[][] = new int[3][3];
// input loop ...
int l = 0, r = 0;
for (int i = 0; i < 3; i++) {
    l += a[i][i];
    r += a[i][3 - i];
}
System.out.println(l);
System.out.println(r);

# a[i][3 - i] is out of bounds
# when i is 0: the program stops.
# No matrix display, unlabelled
# output, no variable description.

We ran this version: it stops with an ArrayIndexOutOfBoundsException on the first pass. Even with the index fixed, it skips the matrix display the question asked for and prints two bare numbers.

import java.util.Scanner;
class Diagonal {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int[][] a = new int[3][3];
    System.out.println("Enter 9 numbers:");
    for (int i = 0; i < 3; i++)
      for (int j = 0; j < 3; j++)
        a[i][j] = sc.nextInt();
    int left = 0, right = 0;
    for (int i = 0; i < 3; i++) {
      left += a[i][i];
      right += a[i][2 - i];
    }
    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++)
        System.out.print(a[i][j] + "\t");
      System.out.println();
    }
    System.out.println("Left diagonal sum = " + left);
    System.out.println("Right diagonal sum = " + right);
  }
}

Input 2 7 6 1 8 3 4 5 9 prints the matrix, then "Left diagonal sum = 19" and "Right diagonal sum = 18". The right diagonal index is 2 - i, the last index minus the row.