#### Boundary elements are those elements which are not surrounded by elements on all four directions, i.e. elements in first row, first column, last row and last column.

##### To learn more about how to print the biggest(Maximum) and the smallest(Minimum) element of the array click the given link. https://java4school.com/double-dimensional-arraymatrix-programs-part-i

**Write a program to accept a matrix of any size from the user an print the sum of the boundary elements of the matrix. **

```
import java.util.*;
public class Boundary_Elements
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
int m, n, sum = 0, row1 = 0, col_n = 0, diag = 0;
System.out.print("\nEnter the no. of rows : ");
m = sc.nextInt();
System.out.print("\nEnter the no. of columns : ");
n = sc.nextInt();
int i, j;
int[][] mat = new int[m][n];
System.out.print("\n Input "+ m*n +" matrix elements \n");
for(i = 0; i < m; i++)
{
for(j = 0; j < n; j++)
{
mat[i][j] = sc.nextInt();
}
}
System.out.println("The original matrix is");
for(i = 0; i < m; i++)
{
for(j = 0; j < n; j++)
{
System.out.print(mat[i][j]+ " ");
}
System.out.println();
}
System.out.print("\n Boundary Matrix: \n");
for(i = 0; i < m; i++)
{
for(j = 0; j < n; j++)
{
if (i == 0 || j == 0 || i == n-1|| j == n - 1)
{
System.out.print(mat[i][j] + " " );
sum = sum + mat[i][j];
}
else
System.out.print(" ");
}
System.out.println( );
}
System.out.print("\n Sum of boundary elements is " + sum);
}
}
```

Output :

Enter the no. of rows : 3

Enter the no. of columns : 3

Input 9 matrix elements

1

2

3

4

5

6

7

8

9

The matrix is

1 2 3

4 5 6

7 8 9

Boundary Matrix

1 2 3

4 6

7 8 9

Sum of boundary elements is 40