# Java Program to Count Total Number of Negative Elements in a Matrix

In the previous article, we have discussed Java Program to Count Total Number of Positive Elements in a Matrix

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

## Java Program to Count Total Number of Negative 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.

Negative elements in a matrix are the elements which are less than 0.

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

### 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 negative 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 negative 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 negative 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 negative elements in the matrix are : 5

### 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 negative 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 negative 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 negative elements in the matrix are : 2

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