Java Program to add two matrices

Program

import java.util.Scanner;
class AddMatrix
{
    public static void main(String[] args) {
        int i, j;
        int row, col;
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter the number of rows for both matrix:\t");
        row = sc.nextInt();
        System.out.println("Enter the number of columns for both matrix:\t");
        col = sc.nextInt();
        int mat1[][] = new int[row][col];
        int mat2[][] = new int[row][col];
        int mat3[][] = new int[row][col];
        System.out.printf("Enter %d elements for matrix 1\n", row * col);
        for (i = 0; i < row; i++)
        {
            for (j = 0; j < col; j++)
            {
                mat1[i][j] = sc.nextInt();
            }
        }
        System.out.printf("Enter %d elements for matrix 2\n", row * col);
        for (i = 0; i < row; i++)
        {
            for (j = 0; j < col; j++)
            {
                mat2[i][j] = sc.nextInt();
            }
        }
        for (i = 0; i < row; i++)
        {
            for (j = 0; j < col; j++)
            {
                mat3[i][j] = mat1[i][j] + mat2[i][j];
            }
        }
        System.out.println("The Addition of two Matrices is:\n");
        for (i = 0; i < row; i++)
        {
            for (j = 0; j < col; j++)
            {
                System.out.printf("%d\t", mat3[i][j]);
            }
            System.out.println("\n");
        }
    }
}

This program performs matrix addition in Java.

1. Input:

   • The program first asks the user for the number of rows and columns for two matrices (mat1 and mat2).
   • It then prompts the user to enter the elements for both matrices.

2. Matrix Addition Logic:

   • The elements of the two matrices are added element by element. The sum of corresponding elements from mat1 and mat2 is stored in a third matrix (mat3).

3. Steps:

   • Matrix Input:
     • Two matrices mat1 and mat2 are created based on the given dimensions (rows and columns).
     • User input is used to fill the elements of these matrices.
   • Matrix Addition:
     • A nested loop iterates over all elements of both matrices, adding the corresponding elements (mat1[i][j] + mat2[i][j]) and storing the result in mat3.
   • Matrix Output:
     • Finally, the result matrix mat3 (sum of the two matrices) is printed row by row.

4. Output:

   • The result matrix is displayed after performing the addition of corresponding elements from mat1 and mat2.

5. Example Execution:

   • Input (for example, a 2x2 matrix):

     Enter the number of rows for both matrix: 2
     Enter the number of columns for both matrix: 2
     Enter 4 elements for matrix 1:
     1 2
     3 4
     Enter 4 elements for matrix 2:
     5 6
     7 8
     

   • Process:
     • Matrix 1:

       1 2
       3 4
       

     • Matrix 2:

       5 6
       7 8
       

     • The sum will be:

       6 8
       10 12
       

   • Output:

     The Addition of two Matrices is:
     6   8   
     10  12  
     

6. Explanation:

   • The program adds matrices element by element:
     • For each element mat3[i][j], it adds mat1[i][j] and mat2[i][j].
   • This program works for any matrix size, as long as both matrices have the same dimensions.

Time Complexity:

• Time Complexity: O(m * n), where m is the number of rows and n is the number of columns. This is because we loop over every element of the matrices to perform the addition.

Space Complexity:

• Space Complexity: O(m * n) for storing the matrices and their sum.

Output

$ javac AddMatrix.java
$ java AddMatrix
Enter the number of rows for both matrix:
3
Enter the number of columns for both matrix:
3
Enter 9 elements for matrix 1
12
56
77
98
14
66
15
38
12
Enter 9 elements for matrix 2
78
96
54
23
85
25
47
66
58
The Addition of two Matrices is:
90      152     131
121     99      91
62      104     70