Java Program to Count Total Number of Positive Elements in a Matrix

In the previous article, we have discussed Java Program to Count the Numbers of 0’s in a Binary Matrix

In this article we are going to see how we can write a program to count the Total Number of Positive Elements in a matrix in JAVA language.

Java Program to Count Total Number of Positive Elements in a Matrix

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.

Positive elements in a matrix are the elements which are greater than 0.

Let’s see different ways to count total number of positive elements in a Matrix.

By Static Initialization of Array Elements
By Dynamic Initialization of Array Elements

Method-1: Java Program to Count Total Number of Negative Elements in a Matrix By Static Initialization of Array Elements

Approach:

Declare and initialize an array of size 3×3, with elements.
Use two for loops to iterate the rows and columns.
Inside the for loops count all the positive elements using a counter.
Print the result.

Program:

public class matrix
{
    public static void main(String args[])
    {
        // Initializing the 3X3 matrix i.e. 2D array
        int arr[][] = {{19,25,-32},{40,-54,-62},{-70,-20,60}};
        int row, col ,count = 0;

        System.out.print("The matrix elements are : ");
        printMatrix(arr);

        // Loops to count total number of positive elements in a matrix
        for(row=0;row<3;row++)
            for(col=0;col<3;col++)
            {
                if(arr[row][col]>0)
                    count++;
            }   
        
        System.out.println("\nNumber of positive elements in the matrix are : "+count);
    }

    // Method to print the matrix
    static void printMatrix(int arr[][])
    {
        int row, col;
        // 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]+" ");
            }
        }
        System.out.print("\n");
    }
}

Output:

The matrix elements are : 
19 25 -32 
40 -54 -62 
-70 -20 60

Number of positive elements in the matrix are : 4

Method-2: Java Program to Count Total Number of Negative Elements in a Matrix By Dynamic Initialization of Array Elements

Approach:

Declare one array of size 3×3.
Ask the user for input of array elements and store them in the array using two for loops.
Use two for loops to iterate the rows and columns .
Inside the for loops count all the negative elements using a counter.
Print the result.

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];
        int row, col ,count = 0;

        // Taking matrix1 input
        System.out.println("Enter matrix elements : ");
        for(row=0;row<3;row++)
            for(col=0;col<3;col++)
                arr[row][col] = scan.nextInt();


        System.out.print("The matrix elements are : ");
        printMatrix(arr);

        // Loops to count total number of positive elements in a matrix
        for(row=0;row<3;row++)
            for(col=0;col<3;col++)
            {
                if(arr[row][col]>0)
                    count++;
            }   
        
        System.out.println("\nNumber of positive elements in the matrix are : "+count);
    }

    // Method to print the matrix
    static void printMatrix(int arr[][])
    {
        int row, col;
        // 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]+" ");
            }
        }
        System.out.print("\n");
    }
}

Output:

Enter matrix elements : 
The matrix elements are : 
0 6 -1 
-2 3 8 
7 0 5

Number of positive elements in the matrix are : 5

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