# Java program to print the boundary elements of a matrix

### 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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## 1 Comment

## Srivalyareddy@gmail.com · December 27, 2019 at 2:30 pm

Traversal of a matrix program in java