Question

/**

* multiply a scalar value (constant) into a matrix.

* IMPORTANT: the matrix passed should NOT be modified.

* @param m: matrix from which scalar is to be subtracted

* @param b: scalar to be subtracted

* @return resulting Matrix

*/

public static Matrix multiply(Matrix m, double b)

{

Matrix result = new Matrix();

return result; //to be completed

}

/**

* add to matrices.

* IMPORTANT: neither of the passed matrices should be modified

* @param m: matrix 1

* @param n: matrix 2

* @return if m and n have the same dimensions, return

* result of adding the two matrices, otherwise return null

*/

public static Matrix add(Matrix m, Matrix n)

{

Matrix result = new Matrix();

return result; //to be completed

}

Answer 1

import java.util.Scanner;
public class Matrix {

   private double[][] array;
  
   public Matrix(int rows, int columns) {
       // TODO Auto-generated constructor stub
       array = new double[rows][columns];
   }
   public Matrix() {
      
   }
  
   public String toString(){
       String res = "";
       if(array==null)
           return res;
       for(int i=0;i<array.length;++i){
           res = res + "\n";
           for(int j=0;j<array[i].length;++j){
               res = res + array[i][j] + "\t";
           }
       }
       return res;
   }
  

/**

* multiply a scalar value (constant) into a matrix.

* IMPORTANT: the matrix passed should NOT be modified.

* @param m: matrix from which scalar is to be subtracted

* @param b: scalar to be subtracted

* @return resulting Matrix

*/

public static Matrix multiply(Matrix m, double b)

{

   if(m.array ==null)
       return null;

  
   Matrix result = new Matrix(m.array.length, m.array[0].length);
   for(int i=0;i<m.array.length;++i){
       for(int j=0;j<m.array[i].length;++j){
           result.array[i][j] = m.array[i][j] *b;
       }
   }

return result; //to be completed

}

/**

* add to matrices.

* IMPORTANT: neither of the passed matrices should be modified

* @param m: matrix 1

* @param n: matrix 2

* @return if m and n have the same dimensions, return

* result of adding the two matrices, otherwise return null

*/

public static Matrix add(Matrix m, Matrix n)

{
   if(m.array ==null || n.array==null)
       return null;

   if((m.array.length != n.array.length)   || (m.array[0].length != n.array[0].length) )
       return null;
  
   Matrix result = new Matrix(m.array.length, m.array[0].length);
   for(int i=0;i<m.array.length;++i){
       for(int j=0;j<m.array[i].length;++j){
           result.array[i][j] = m.array[i][j] + n.array[i][j];
       }
   }

return result; //to be completed

}

   public static void main(String[] args) {
       // TODO Auto-generated method stub
      
       Matrix m = new Matrix(2, 2);
       Scanner sc = new Scanner(System.in);
       System.out.println("Enter values: ");
       for(int i=0;i<m.array.length;++i){
           for(int j=0;j<m.array[i].length;++j){
               m.array[i][j] = sc.nextInt();
           }
       }
       System.out.println("Matrix is:");
       System.out.println(m.toString());
       Matrix mat = add(m, m);
      
       System.out.println(" Add Matrix m + m is:");
       System.out.println(mat.toString());
      
       Matrix mat1 = multiply(m, 10);
      
       System.out.println("Multiply Matrix m by 10 is:");
       System.out.println(mat1.toString());  

   }

}

======================================
See Output

58 return result; //to be completed 59 60 61 62 63 640/** 65 66 add to matrices. 67 68 IMPORTANT: neither of the passed matrices should be modified 69 70 @param m: matrix 1 71 72 @param n: matrix2 73 74*@return if m and n have the same dimensions, return 75 76 * result of adding the two matrices, otherwise return null <terminated> Matrix [Java Application] /Lib Enter values: 4 Matrix is 2.0 4.0 3.0 5.0 Add Matrix m m is: 4.0 8.0 Multiply Matrix m by 10 is: 6.0 10.0 20.0 30.0 40.0 50.0 78 * 79 80 public static Matrix add(Matrix m, Matrix n) 81 82 83 84 85 86 87 if(m.arraynull II n.array null) return null; if((m.array.length- n.array.length) (m.array[0].length !- n return null; Matrix result- new Matrix(m.array.length, m.array[0].length); for(int i-0;i<m.array.length;++i) 89 90 91 92 93 94 95 96 return result; //to be completed 97 forCint j-0;j<m.arrayLi].length;++j)I result.array[i]Lj]m.array[i][j] + n.array[i]lj];


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