Create a Matrix and Fill Primary Diagonal with 1 and Secondary Diagonal with 2

In Java, a matrix can be represented using a two-dimensional array. Matrices are used for storing and manipulating data that have a tabular structure. Matrices have several properties and operations associated with them, such as addition, subtraction, multiplication, transposition, and determinant calculation.

As per the problem statement we have to Create a Matrix and Fill Primary Diagonal with 1 and Secondary Diagonal with 0.

Let's start!

For instance

Suppose we have 4*4 matrix i.e. 4 rows and 4 columns.

After performing the operation on matrix, the result will be:

Enter the size of the matrix: 4

The resultant matrix is:

1 0 0 0 
0 1 0 0 
0 0 1 0 
0 0 0 1 

Algorithm

Step-1: Define the size of the matrix.

Step-2: Create a square matrix of size 'size'.

Step-3: Fill 1 on the primary diagonal and 0 on the secondary diagonal.

Step-4: Print the result.

Multiple Approaches

We have provided the solution in different approaches.

• By Using Static Initialization of Matrix Elements

• By Using User Defined Method

Let's see the program along with its output one by one.

Approach-1: By Using Static Initialization of Array Elements

In this approach, matrix elements will be initialized in the program. Then as per the algorithm Create a Matrix and Fill Primary Diagonal with 1 and Secondary Diagonal with 0.

Example

import java.util.Scanner;
public class Main 
{
   public static void main(String[] args) 
   {
      Scanner scanner = new Scanner(System.in);
      // Define the size of the matrix
      System.out.print("Enter the size of the matrix: ");
      int size = scanner.nextInt();
      // Create a square matrix of size 'size'
      int[][] matrix = new int[size][size]; 
      // Filling the matrix 
      for (int i = 0; i < size; i++) {
         for (int j = 0; j < size; j++) {
            if (i == j) {
               // Filling 1 on the primary diagonal
               matrix[i][j] = 1; 
            } else if (i + j == size - 1) {
               // Filling 0 on the secondary diagonal
               matrix[i][j] = 0; 
            }
         }
      }
      // Print the matrix
      System.out.println("The resultant matrix is:");
      for (int i = 0; i < size; i++) {
         for (int j = 0; j < size; j++) {
            System.out.print(matrix[i][j] + " ");
         }
         System.out.println();
      }
   }
}

Output

Enter the size of the matrix: 4
The resultant matrix is:
1 0 0 0 
0 1 0 0 
0 0 1 0 
0 0 0 1

Approach-2: By Using User Defined Method

In this approach, matrix elements will be initialized in the program. Then call a user defined method by passing the matrix as parameter and inside method as per the algorithm create a matrix and fill primary diagonal with 1 and secondary diagonal with 0.

Example

import java.util.Scanner;
public class Main 
{
   public static void main(String[] args) 
   {
      // taking the dimension of the matrix 
      Scanner scanner = new Scanner(System.in);
      // Define the size of the matrix
      System.out.print("Enter the size of the matrix: ");
      int size = scanner.nextInt();
      // calling user defined method
      func(size);   
   }
   // user defined method
    public static void func(int size)
   {
      // Create a square matrix of size 'size'
      int[][] matrix = new int[size][size]; 
      // Filling the matrix 
      for (int i = 0; i < size; i++) {
         for (int j = 0; j < size; j++) {
            if (i == j) {
               // Filling 1 on the primary diagonal
               matrix[i][j] = 1; 
            } else if (i + j == size - 1) {
               // Filling 0 on the secondary diagonal
               matrix[i][j] = 0; 
            }
         }
      }
      // Print the matrix
      System.out.println("The resultant matrix is:");
      for (int i = 0; i < size; i++) {
         for (int j = 0; j < size; j++) {
            System.out.print(matrix[i][j] + " ");
         }
         System.out.println();
      }
   }
}

Output

Enter the size of the matrix: 5
The resultant matrix is:
1 0 0 0 0 
0 1 0 0 0 
0 0 1 0 0 
0 0 0 1 0 
0 0 0 0 1

In this article, we explored how to create a matrix and fill primary diagonal with 1 and secondary diagonal with 0 by using Java programming language.