Write a program to create a square matrix of size [m × m] of type integer.

The value of ‘m’ is entered by the user and ensure that m > 3 and m < 10.

For an invalid size, display a suitable error message.

Now allow the user to enter integers into this matrix.

Once the array is full with integers, display the elements that fall above the right diagonal.

**Example:**

INPUT:

M = 4

Original Matrix:

1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7

OUTPUT:

Elements above right diagonal:

1 2 3 5 6 9

```
import java.io.*;
class RightDiagonal{
public static void main(String args[])throws IOException{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Matrix size: ");
int m = Integer.parseInt(br.readLine());
if(m < 4 || m > 9){
System.out.println("Size out of range!");
return;
}
int a[][] = new int[m][m];
System.out.println("Enter matrix elements:");
for(int i = 0; i < m; i++){
for(int j = 0; j < m; j++){
a[i][j] = Integer.parseInt(br.readLine());
}
}
System.out.println("Original matrix:");
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("Elements above right diagonal:");
for(int i = 0; i < m; i++){
for(int j = 0; j < m; j++){
if(i + j < m - 1)
System.out.print(a[i][j] + "\t");
else
System.out.print("\t");
}
System.out.println();
}
}
}
```

Sir,a program is given which states that:

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:

INPUT: N = 4

FIRST CHARACTER: @

SECOND CHARACTER: ?

THIRD CHARACTER: #

OUTPUT: @ ? ? @

? # # ?

? # # ?

@ ? ? @

Use Scanner class

Here is the link to the solution for filling the matrix with three characters.