Java program to declare a square matrix and fill the data based on given criteria

Write a program to declare a square matrix M [ ] [ ] of order ‘N’ where ‘N’ must be greater than 3 and less than 10. Allow the user to accept three different characters from the keyboard and fill the array according to the instruction given below:

(i) Fill the four corners of the square matrix by character 1.

(ii) Fill the boundary elements of the matrix (except the four corners) by character 2.

(iii) Fill the non-boundary elements of the matrix by character 3.

Test your program with the following data and some random data:

Example 1:

INPUT: N = 4

FIRST CHARACTER: @

SECOND CHARACTER: ?

THIRD CHARACTER: #

OUTPUT:

@ ? ? @

? # # ?

? # # ?

@ ? ? @

Example 2:

INPUT: N = 5

FIRST CHARACTER: A

SECOND CHARACTER: C

THIRD CHARACTER: X

OUTPUT:

A C C C A

C X X X C

C X X X C

C X X X C

A C C C A

Example 3:

INPUT: N = 12

OUTPUT: SIZE OUT OF RANGE

import java.util.*;
class SquareMatrix
{
    public static void main(String arr[])
    {
        Scanner sc=new Scanner(System.in);
        int n;
        char M[][]=new char[10][10];
        System.out.println("Enter the value of n : ");
        n=sc.nextInt();
        sc.nextLine();
        if(n<3 || n>10)
        {
             System.out.println("Invalid Input");
             System.exit(0);
        }
        System.out.println("Enter the Charcter 1 : ");
        char ch1=sc.next().charAt(0);
        System.out.println("Enter the Charcter 2 : ");
        char ch2=sc.next().charAt(0);
        System.out.println("Enter the Charcter 3 : ");
        char ch3=sc.next().charAt(0);
        for(int a=0;a<n;a++)
        {
            for(int b=0;b<n;b++)
            {
                if((a==0||a==n-1)&&(b==0||b==n-1))
                {
                    M[a][b]=ch1;
                }
                else if(a==0||a==n-1)
                {
                    M[a][b]=ch2;
                }
                else 
                {
                    M[a][b]=ch3;
                }
            }
        }
        
        for(int a=0;a<n;a++)
        {
            for(int b=0;b<n;b++)
            {
                System.out.print(M[a][b]+" ");
            }
            System.out.println();
        }
    }
}

Enter the value of n : 

5

Enter the Charcter 1 : 

@

Enter the Charcter 2 : 

#

Enter the Charcter 3 : 

%

@ # # # @ 

% % % % % 

% % % % % 

% % % % % 

@ # # # @