### Java program to print the boundary elements of a matrix :

In this tutorial, we will learn how to print the *boundary elements of a matrix* using Java. For example, for the below matrix :

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

The matrix with boundary elements will be as below :

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

### Algorithm to solve this problem :

- First, ask the user to input the
*row*and*column*number for the matrix. - Create one matrix with same row and column as the user entered.
- Read all elements for the matrix.
- Print the boundary elements of the user given matrix. Print the first row, last row, first column and last column elements. For other elements, print one blank.

### Java Program :

```
import java.util.Scanner;
class Main {
public static void main(String args[]) {
//1
int row, col;
//2
Scanner scanner = new Scanner(System.in);
System.out.println("Enter total number of rows : ");
row = scanner.nextInt();
//3
System.out.println("Enter total number of columns : ");
col = scanner.nextInt();
//4
int inputArray[][] = new int[row][col];
//5
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
System.out.println("Enter element for array[" + (i + 1) + "," + (j + 1) + "] : ");
inputArray[i][j] = scanner.nextInt();
}
}
//6
System.out.println("You have entered : ");
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
System.out.print(inputArray[i][j] + "\t");
}
System.out.println();
}
//7
System.out.println("The boundary elements of this matrix are : ");
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
if (i == 0 || j == 0 || i == row - 1 || j == col - 1) {
System.out.print(inputArray[i][j] + "\t");
} else {
System.out.print("\t");
}
}
System.out.println();
}
}
}
```

### Explanation :

*The commented numbers in the above program denote the step-number below :*

- Create two integer variables
*row*and*col*to store the row and column count for the matrix. - Create one
*Scanner*object to read user input numbers. Ask the user to enter the total number of rows for the matrix and save it in*row*variable. - Similarly, ask the user to enter the total number of columns for the matrix and save it in
*col*variable. - Create one two dimensional integer array of size
*[row][column]*using the user input values. - Run two
*for loops*to read all elements for the matrix. Read and store it in the two dimensional array. - After all items are stored, print out all elements again using two
*for loops*. - Now, print out the boundary elements of the matrix. We have two
*for loops*here. The outer loop runs from*i=0*to*i=row - 1*and the inner loop runs from*j=0*to*j=col-1*. We need to print the elements for*first row,last row, first column and last column*. Print these elements and for other elements, print one tab*(‘\t’)*.

### Sample Output :

```
Enter total number of rows :
3
Enter total number of columns :
3
Enter element for array[1,1] :
1
Enter element for array[1,2] :
2
Enter element for array[1,3] :
3
Enter element for array[2,1] :
4
Enter element for array[2,2] :
5
Enter element for array[2,3] :
6
Enter element for array[3,1] :
7
Enter element for array[3,2] :
8
Enter element for array[3,3] :
9
You have entered :
1 2 3
4 5 6
7 8 9
The boundary elements of this matrix are :
1 2 3
4 6
7 8 9
```

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