Matrix addition and subtraction in java

Hello everyone!! Welcome to flower brackets blog. In this post we are going to learn matrix addition and subtraction in java.

A matrix represents a two-dimensional array. Here user enters the number of rows and columns.

Also read – matrix transpose java

Nested for loop is used to read the input. Outer for loop “m” ranges from 0 to number of rows of the matrix.

Meanwhile inner for loop “n” ranges from 0 to number of columns of matrix. The input is read using “nextInt()” method of class Scanner and stored at x[m][n] and y[m][n] position.

Also read – matrix multiplication in java

After reading elements, two for loops is used to add two matrices with loop index. Then finally result is stored at z[m][n] position.

Here’s the java program to add two matrices,

import java.util.Scanner;

public class MatrixAdditionDemo
{
   public static void main(String[] args)
   {
      Scanner sc = new Scanner(System.in);
      System.out.println("Please enter number of rows : ");
      int row = sc.nextInt();
      System.out.println("Please enter number of columns : ");
      int col = sc.nextInt();

      int x[][] = new int[row][col];
      int y[][] = new int[row][col];

      System.out.println("Please enter first matrix - ");
      for(int m = 0; m < row; m++)
      {
         for(int n = 0; n < col; n++)
         {
            x[m][n] = sc.nextInt();
         }
      }

      System.out.println("Please enter second matrix - ");
      for(int m = 0; m < row; m++)
      {
         for(int n = 0; n < col; n++)
         {
            y[m][n] = sc.nextInt();
         }
      }

      int z[][] = new int[row][col];
      for(int m = 0; m < row; m++)
      {
         for(int n = 0; n < col; n++)
         {
            z[m][n] = x[m][n] + y[m][n];
         }
      }

      System.out.println("The addition of two matrices is - ");     
      for(int m = 0; m < row; m++)
      {
         for(int n = 0; n < col; n++)
         {
            System.out.print(z[m][n] + " ");
         }
         System.out.println();
      }
   }
}

Output:

Similar to matrix addition we can write java program to subtract two matrices as well. So let’s get our hands dirty,

import java.util.Scanner;

public class MatrixAdditionDemo
{
   public static void main(String[] args)
   {
      Scanner sc = new Scanner(System.in);
      System.out.println("Please enter number of rows : ");
      int row = sc.nextInt();
      System.out.println("Please enter number of columns : ");
      int col = sc.nextInt();

      int x[][] = new int[row][col];
      int y[][] = new int[row][col];

      System.out.println("Please enter first matrix - ");
      for(int m = 0; m < row; m++)
      {
         for(int n = 0; n < col; n++)
         {
            x[m][n] = sc.nextInt();
         }
      }

      System.out.println("Please enter second matrix - ");
      for(int m = 0; m < row; m++)
      {
         for(int n = 0; n < col; n++)
         {
            y[m][n] = sc.nextInt();
         }
      }

      int z[][] = new int[row][col];
      for(int m = 0; m < row; m++)
      {
         for(int n = 0; n < col; n++)
         {
            z[m][n] = x[m][n] - y[m][n];
         }
      }

      System.out.println("The subtraction of two matrices is - ");
      for(int m = 0; m < row; m++)
      {
         for(int n = 0; n < col; n++)
         {
            System.out.print(z[m][n] + " ");
         }
         System.out.println();
      }
   }
}

Output: