to check for Diagonal Matrix

Write a Program in Java to input a 2-D square matrix and check whether it is a Diagonal Matrix or not.

Diagonal Matrix : A diagonal matrix is a matrix (usually a square matrix) in which the entries outside the main diagonal () are all zero. The diagonal entries themselves may or may not be zero (but all diagonal entries cannot be zero).

Example:

import java.util.*;

class DiagonalMatrix

{

    public static void main(String args[])throws Exception

    {

        Scanner sc=new Scanner(System.in);

        System.out.print("Enter the size of the matrix : ");

        int m=sc.nextInt();

        int A[][]=new int[m][m];

         

        /* Inputting the matrix */

        for(int i=0;i<m;i++)

        {

            for(int j=0;j<m;j++)

            {

                System.out.print("Enter an element : ");

                A[i][j]=sc.nextInt();

            }

        }

 

        /* Printing the matrix */

        System.out.println("*************************");

        System.out.println("The Matrix is : ");

        for(int i=0;i<m;i++)

        {

            for(int j=0;j<m;j++)

            {

                System.out.print(A[i][j]+"\t");

            }

            System.out.println();

        }

        System.out.println("*************************");

 

        int p=0, q=0;

         

        for(int i=0;i<m;i++)

        {

            for(int j=0;j<m;j++)

            {

                if(i!=j && A[i][j]!=0) // Checking non-diagonal elements

                {

                    p=1;

                    break;

                }

                if(i==j && A[i][j]==0) // Checking diagonal elements

                {

                    q++;

                }

            }

        }

         

        if(p==0 && q<m)

            System.out.println("The matrix is Diagonal");

        else

            System.out.println("The matrix is not Diagonal");

    }

}




Output:

Enter the size of the matrix : 4
Enter an element : 5
Enter an element : 0
Enter an element : 0
Enter an element : 0
Enter an element : 0
Enter an element : 1
Enter an element : 0
Enter an element : 0
Enter an element : 0
Enter an element : 0
Enter an element : 0
Enter an element : 0
Enter an element : 0
Enter an element : 0
Enter an element : 0
Enter an element : 7
*************************
The Matrix is :
5 0 0 0
0 1 0 0
0 0 0 0
0 0 0 7
*************************
The matrix is Diagonal