Question

Define a class to accept values into an integer array of order 4 x 4 and check whether it is a DIAGONAL array or not An array is DIAGONAL if the sum of the left diagonal elements equals the sum of the right diagonal elements. Print the appropriate message.

Example:

3 4 2 5   Sum of the left diagonal elements =

2 5 2 3   3 + 5 + 2 + 1 = 11

5 3 2 7   Sum of the right diagonal elements =

1 3 7 1   5 + 2 + 3 + 1 = 11

Answer 1

import java.util.*;
class DiagonalArray
{
   public static void main(String arg[]) 
   {
     Scanner sc=new Scanner(System.in);
     int mat[][]=new int[4][4]; 
     int i,j;
     //initializing the array
     System.out.println("Enter the array elements");
     for(i=0;i<4;i++)
     {
       for(j=0;j<4;j++)
       mat[i][j]=sc.nextInt();
     }
     //adding both the diagonal elements
     int ld=0,rd=0;
     for(i=0;i<4;i++)
     {
       for(j=0;j<4;j++)
       {
         if(i==j)
         Id+=mat[i][j];
         if(i+j==3)
         rd+=mat[i][j];
       }
     }
     //checking both the sums
     if(ld=rd)
       System.out.println("It is a DIAGONAL array");
       else
       System.out.println("It is not a DIAGONAL array");
   }
}                  

Output:

Enter the array elements

3 4 2 5

2 5 2 3

5 3 2 7

1 3 7 1

It is a DIAGONAL array