﻿ Java exercises: Add two matrices of the same size - w3resource # Java Array Exercises: Add two matrices of the same size

## Java Array: Exercise-19 with Solution

Write a Java program to add two matrices of the same size.

Pictorial Presentation: Sample Solution:

Java Code :

``````import java.util.Scanner;
public class Exercise19 {
public static void main(String args[])
{
int m, n, c, d;
Scanner in = new Scanner(System.in);

System.out.println("Input number of rows of matrix");
m = in.nextInt();
System.out.println("Input number of columns of matrix");
n  = in.nextInt();

int array1[][] = new int[m][n];
int array2[][] = new int[m][n];
int sum[][] = new int[m][n];

System.out.println("Input elements of first matrix");

for (  c = 0 ; c < m ; c++ )
for ( d = 0 ; d < n ; d++ )
array1[c][d] = in.nextInt();

System.out.println("Input the elements of second matrix");

for ( c = 0 ; c < m ; c++ )
for ( d = 0 ; d < n ; d++ )
array2[c][d] = in.nextInt();

for ( c = 0 ; c < m ; c++ )
for ( d = 0 ; d < n ; d++ )
sum[c][d] = array1[c][d] + array2[c][d];

System.out.println("Sum of the matrices:-");

for ( c = 0 ; c < m ; c++ )
{
for ( d = 0 ; d < n ; d++ )
System.out.print(sum[c][d]+"\t");

System.out.println();
}
}
}
```
```

Sample Output:

```Input number of rows of matrix
2
Input number of columns of matrix
2
Input elements of first matrix
1
2
3
4
Input the elements of second matrix
5
6
7
8
Sum of the matrices:-
6       8
10      12
```

Flowchart: Java Code Editor:

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## Java: Tips of the Day

Array vs ArrayLists:

The main difference between these two is that an Array is of fixed size so once you have created an Array you cannot change it but the ArrayList is not of fixed size. You can create instances of ArrayLists without specifying its size. So if you create such instances of an ArrayList without specifying its size Java will create an instance of an ArrayList of default size.

Once an ArrayList is full it re-sizes itself. In fact, an ArrayList is internally supported by an array. So when an ArrayList is resized it will slow down its performance a bit as the contents of the old Array must be copied to a new Array.

At the same time, it's compulsory to specify the size of an Array directly or indirectly while creating it. And also Arrays can store both primitives and objects while ArrayLists only can store objects.

Ref: https://bit.ly/3o8L2KH