Sum of secondary diagonal of a matrix in Java

In the last tutorial, we learned about the sum of the principal diagonal of a matrix, in this tutorial we will see how to find the sum of the secondary diagonal of a matrix in Java.

Have a look at the below matrix:

A1     A2     A3

B1     B2     B3

C1     C2     C3

Here the principal diagonal is A3 – B2- C1, and our task is to find the sum of these elements.

It has to be noted that the matrix can be of any dimension, though it needs to be a square matrix.

Java program to find the sum of secondary diagonal of a matrix in Java

Here is how the code will look:

import java.util.*;
public class test
{
  public static void main(String[] args)
  {
       
       Scanner sc=new Scanner(System.in);
       int arr[][]=new int[3][3];
       int dsum=0;
       System.out.println("Enter elements in matrix");
       for(int i=0;i<=2;i++)
       {
    	   for(int j=0;j<=2;j++)
    	   {
    		   arr[i][j]=sc.nextInt();
    		   if(i+j==2)
    		   {
    			   dsum=dsum+arr[i][j];
    		   }
    	   }
    	   
       }
       System.out.println("The sum of secondary principal diagonal is "+dsum);
       
       
       
  }
}
       

This will generate the following output:

Enter elements in matrix
1
2
3
4
5
6
7
8
9
The sum of secondary principal diagonal is 15

Hope this helped you out.

Also read:

• Maximum sum of an Hourglass in a Matrix in Java
• How to Find Saddle Point of a Matrix in Java

One response to “Sum of secondary diagonal of a matrix in Java”

1. m lokesh gupta says:

   January 11, 2023 at 11:46 am

   it works only for 3×3 matrix because the condition says i+j==2 this statement for only 3×3

   Reply