Question

Java.

Write 3 methods named addArrays, subArrays, and mulArrays each.

addArrays gets two matrices(int [][] array1, int [][] array2) as parameters and add them and returns the result (matrix).

subArrays gets two matrices(int [][] array1, int [][] array2) as parameters and subtract array2 from array1 and returns the result (matrix).

mulArrays gets two matrices(int [][] array3, int [][] array4) as parameters, multiplying them and returning the result(matrix).

Answer 1

import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.Scanner;

/* Name of the class has to be "Main" only if the class is public. */
class Codechef
{
public static int [][]addArrays(int [][]arr1, int [][]arr2,int rows,int col)
{
int [][]c = new int[rows][col];
for(int i = 0; i < rows ; i++)
for(int j = 0; j < col; j++)
{
c[i][j] = arr1[i][j] + arr2[i][j];
}
return c;
}
public static int [][]subArrays(int [][]arr1, int [][]arr2,int rows,int col)
{
int [][]c = new int[rows][col];
for(int i = 0; i < rows ; i++)
for(int j = 0; j < col; j++)
{
c[i][j] = arr1[i][j] - arr2[i][j];
}
return c;
}
//m is rows of first matrix, p is rows and q is col of second matrix
public static int [][]mulArrays(int [][]arr1, int [][]arr2,int m,int p,int q)
{
int [][]multiply = new int[m][q];
int sum = 0;
for(int c=0; c<m; c++)
{
for(int d=0; d<q; d++)
{   
for(int k=0; k<p; k++)
{
sum = sum + arr1[c][k]*arr2[k][d];
}

multiply[c][d] = sum;
sum = 0;
}
}
return multiply;
}

   public static void main (String[] args) throws java.lang.Exception
   {
       // your code goes here
   Scanner in = new Scanner(System.in);
   System.out.print("Enter Number of Rows and Columns of First Matrix : ");
int m = in.nextInt();
int n = in.nextInt();
  
int arr1[][] = new int[m][n];
  
System.out.print("Enter First Matrix Elements : ");
  
for(int c=0 ; c<m; c++)
{
for(int d=0; d<n; d++)
{
arr1[c][d] = in.nextInt();
}
}
System.out.print("Enter Number of Rows and Columns of Second Matrix : ");
int p = in.nextInt();
int q = in.nextInt();

int arr2[][] = new int[p][q];
  
System.out.print("Enter Second Matrix Elements :\n");

for(int c=0; c<p; c++)
{
for(int d=0; d<q; d++)
{
arr2[c][d] = in.nextInt();
}
}

//check matrix addition
  
if(m == p && n == q)
{
int add[][] = new int[p][q];
int sub[][] = new int[p][q];
add = addArrays(arr1,arr2,m,n);
System.out.print("Addition of two Matrices is :\n");

for(int c=0; c<m; c++)
{
for(int d=0; d<n; d++)
{
System.out.print(add[c][d] + "\t");
}
System.out.print("\n");
}
System.out.print("Subtraction of two Matrices is :\n");
sub = subArrays(arr1,arr2,m,n);
for(int c=0; c<m; c++)
{
for(int d=0; d<n; d++)
{
System.out.print(sub[c][d] + "\t");
}
System.out.print("\n");
}
}
else
System.out.print("two Matrices can not be added or subtracted\n");
if ( n != p )
{
System.out.print("Matrix of the entered order can't be Multiplied..!!");
}
else
{
int mul[][] = new int[p][q];
mul = mulArrays(arr1,arr2,m,p,q);
System.out.print("Multiplication of two Matrices is :\n");

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

   }
  

}

-------------------------------------------------------------------------------------------------------------------------------------------------------------------

//input:

2 3

1        2        3       

7        8        9

2 3

5        6        7       

3        4        5

//output

Addition of two Matrices is :

6        8        10     

10      12      14     

Subtraction of two Matrices is :

-4      -4      -4     

4        4        4       

//input for multiplication

2 3

1 2 3

4 5 6

3 2

7 8

9 10

11 12

//output

Multiplication of two Matrices is :

58      64     

139    154