Java Program to Find Average of Matrix Elements

Java Program to Find Average of Matrix Elements

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In the previous article, we have seen Java Program to Find Product of Sum of First Column and Last Column

In this article we are going to see how we can write a program to calculate the average of matrix elements in JAVA language.

Java Program to Find Average of Matrix Elements

A 3*3 Matrix is having 3 rows and 3 columns where this 3*3 represents the dimension of the matrix. Means there are 3*3 i.e. total 9 elements in a 3*3 Matrix.

Let’s understand it in more simpler way.

                   | A00   A01   A02 |
Matrix A =  | A10   A11   A12 |
                   | A20   A21   A22 | 3*3
  • Matrix A represents a 3*3 matrix.
  • ‘A‘ represents the matrix element
  • ‘Aij‘ represents the matrix element at it’s matrix position/index.
  • ‘i‘ represents the row index
  • ‘j‘ represents the column index
  • Means A00=Aij  where i=0 and j=0,  A01=aij where i=0 and j=1 and like this.
  • Here we have started row value from 0 and column value from 0.

Let’s see different ways to find average of matrix elements.

Method-1: Java Program to Find Average of Matrix Elements By Static Initialization of Array Elements

Approach:

  • Initialize and declare an array of size 3×3 with elements.
  • Use two for loops to iterate the rows and columns and then add each element to the sum variable.
  • Then find the average by dividing the sum by 9(As in a 3*3 matrix there are total 9 elements).
  • Print the average.

Program:

import java.util.Scanner;

public class Matrix
{
    public static void main(String args[])
    {
        //Scanner class to take input
        Scanner scan = new Scanner(System.in);

        // Initializing the 3X3 matrix i.e. 2D array
        int arr[][] = {{10,20,30},{40,50,60},{70,80,90}};
        int row, col, sum = 0;
        
        System.out.print("The matrix elements are : ");
        // Loop to print the elements
        for(row=0;row<3;row++)
        {
            // Used for formatting
            System.out.print("\n");
            for(col=0;col<3;col++)
            {
                System.out.print(arr[row][col]+" ");
            }
        }

        //finding the sum of elements
        for(row=0;row<3;row++)
            for(col=0;col<3;col++)
                sum+=arr[row][col];

        System.out.print("\nThe sum of all the elements of matrix is : "+sum);
        
        //Finding the average of all elements of matrix
        //There are total 9 elements in a 3*3 matrix
        //so we are dividing the sum by 9
        int avg=sum/9;
        
        System.out.print("\nThe average of all the elements of matrix is : "+avg);
    }
}
Output:

The matrix elements are : 
10 20 30 
40 50 60 
70 80 90 
The sum of all the matrix elements is : 450
The average of all the matrix elements is : 50

Method-2: Java Program to Find Average of Matrix Elements By Dynamic Initialization of Array Elements

Approach:

  • Initialize an array of size 3×3.
  • Ask the user for input.
  • Use two for loops to iterate the rows and columns and input the array elements.
  • Similarly use two for loops to add each element and store in sum variable.
  • Then find the average by dividing the sum by 9(As in a 3*3 matrix there are total 9 elements).
  • Print the average.

Program:

import java.util.Scanner;

public class Matrix
{
    public static void main(String args[])
    {
        //Scanner class to take input
        Scanner scan = new Scanner(System.in);
        // Initializing the 3X3 matrix i.e. 2D array
        int arr[][] = new int[3][3], sum = 0;
        
        System.out.println("Enter the 3x3 matrix elements : ");
        int row, col;
        
        // Loop to take user input
        for(row=0;row<3;row++)
            for(col=0;col<3;col++)
                arr[row][col] = scan.nextInt();
        
        System.out.print("The matrix elements are : ");
        // Loop to print the elements
        for(row=0;row<3;row++)
        {
            // Used for formatting
            System.out.print("\n");
            for(col=0;col<3;col++)
            {
                System.out.print(arr[row][col]+" ");
            }
        }

        //finding the sum of elements
        for(row=0;row<3;row++)
            for(col=0;col<3;col++)
                sum+=arr[row][col];

        System.out.print("\nThe sum of all the elements of matrix is : "+sum);
        
        //Finding the average of all elements of matrix
        //There are total 9 elements in a 3*3 matrix
        //so we are dividing the sum by 9
        int avg=sum/9;
        
        System.out.print("\nThe average of all the elements of matrix is : "+avg);
    }
}
Output:

Enter the 3x3 matrix elements : 
The matrix elements are : 9 5 1 7 4 8 2 6 3 
9 5 1 
7 4 8 
2 6 3 
The sum of all the elements of matrix is : 45
The average of all the elements of matrix is : 5

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