Answer to Question #192661 in C++ for MOHID

Question

Implement a class Matrix as defined below. class Matrix { public: Matrix(); //create a matrix of size 2X2 Matrix(int r,int c); // create a matrix with r rows and c columns Matrix(const Matrix & m); //copy constructor , create a deep copy of //matrix m Matrix operator+(const Matrix &); Matrix operator-(const Matrix &); Matrix operator*(const Matrix &); bool operator==(const Matrix &); bool operator!=(const Matrix &); Friend ostream& operator<<(ostream& ,Matrix &); Friend istream& operator>>(istream& ,Matrix &); bool isIdentity(); //returns true if matrix is identity matrix 3 | P a g e void transpose(); //transpose of matrix void inverse(); // inverse of matrix void adjoint(); //adjoint of matrix int getElement(int r,int c); // returns element at row r and col c int determinant(); //find the determinant void fillMatrix(); // fill matrix by taking input from user void print(); ~Matrix(); private: int ** data; int rows; int cols; };

Answer 1

#include <iostream>

using namespace std;

#include <iostream>

using namespace std;

class Matrix{

private:

int rows, columns;

public:

int **arr; // Creating a 2D array dynamically

  

bool Check(Matrix a, Matrix b); //Check function

  

Matrix(int r, int c);

Matrix add(Matrix a, Matrix b);

Matrix subtract(Matrix a, Matrix b);

Matrix multiply(Matrix a, Matrix b);

Matrix scalar(Matrix a, int b);

void printMatrix(Matrix a);

int getRows()const{

return rows;

}

int getColumns()const{

return columns;

}

~Matrix(); //Destructor

};

Matrix::Matrix(int r, int c){

this->rows = r;

this->columns = c;

arr = new int*[this->rows];

for(int i=0; i < this->rows; i++)

arr[i]= new int[this->columns];

}

bool Matrix::Check(Matrix a, Matrix b){

if(a.rows == b.rows && a.columns == b.columns)

return true;

return false;

}

Matrix Matrix:: add(const Matrix a, Matrix b){

Matrix c(a.rows, a.columns);

if(a.Check(a, b)) //Calling the method Check() using Matrix object -- a

{

if((a.rows == b.rows)&&(a.columns == b.columns)){

   for(int i =0; i < a.rows; i++){

for (int j =0; j < a.columns; j++){

c.arr[i][j] = a.arr[i][j]+b.arr[i][j];

}

}

}

}return c;

}

Matrix Matrix:: subtract(const Matrix a, Matrix b){ //subtraction

if(a.rows == b.rows && a.columns == b.columns){

cout<<"The subtraction is not possible!"<<endl;

}

Matrix c(a.rows, a.columns);

{

for(int i =0; i < a.rows; i++){

for (int j =0; j < a.columns; j++)

c.arr[i][j] = a.arr[i][j]-b.arr[i][j];

}

}

return c;

}

Matrix Matrix::multiply(const Matrix a, Matrix b)

{

int ar=a.rows;

int ac=a.columns;

int br=b.rows;

int bc=b.columns;

if(ac != br)

{

cout<<"Matrix multiplication is not possible. \n ";

Matrix d(0,0);

return d;

}

Matrix c(ar,bc); //create a new object

for (int i=0; i < ar; i++)

{

for(int j =0; j < bc; j++){

c.arr[i][j] =0;

for(int k =0; k <ac; k++){

c.arr[i][j] += a.arr[i][k] * b.arr[k][j];

}

}

}

return c;

}

Matrix Matrix::scalar(Matrix a, int s){ //Scalar

Matrix c(a.rows, a.columns);

for(int i=0; i < c.rows; i++)

{

for (int j =0; j < c.columns; j++){

c.arr[i][j] = a.arr[i][j]*s;

}

}

return c;

}

void Matrix::printMatrix(Matrix a){

for (int i =0; i < a.rows; i++){

for (int j = 0; j < a.columns; j++){

cout<<a.arr[i][j]<<" ";

}

cout<<endl;

}

}

Matrix::~Matrix(){ //Free each sub-array

//delete arr;

//Free the array of pointers

this->rows = 0;

this->columns = 0;

//cout<<"Destroyed"<<this->arr[0][0];

}

int main() {

int row1, column1, row2,column2;

bool check;

//Let the user enter the values for first Matrix1

cout<<"Please enter the Rows and Columns in Matrix1."<<endl;

cin>>row1>>column1;

Matrix a(row1, column1); // Creating matrix 1

cout<<"Enter the values of Matrix 1. "<<endl;

for(int i=0; i < row1; i++){

for(int j=0; j< column1; j++){

cin>>a.arr[i][j];

}

}

//Let the user enter the values for first Matrix2

cout<<"Please enter the Rows and Columns in Matrix2."<<endl;

cin>>row2>>column2;

Matrix b(row2, column2); // Creating matrix 2

cout<<"Enter the values of Matrix 2. "<<endl;

for(int i=0; i < row2; i++){ //Let the user to enter the values

for(int j=0; j< column2; j++){

cin>>b.arr[i][j];

}

}

// Print Martix 1

cout<<" \nMatrix 1 "<<endl;

a.printMatrix(a);

// Print Martix 2

cout<<" \nMatrix 2 "<<endl;

b.printMatrix(b);

cout<<"\nThe addition of 1 and 2 is "<<endl; //Addition

if(Check(a,b))

{

Matrix c = a.add(a,b);

c.printMatrix(c);

}

else

cout<<"This cannot be add!"<<endl;

cout<<"\nThe subtraction of 1 and 2 is "<<endl; //Subtraction

Matrix d = a.subtract(a,b);

//condition

d.printMatrix(d);

  

cout<<"\nThe multiplication of 1 and 2 is "<<endl; //Multiplication

Matrix e = a.multiply(a,b);

e.printMatrix(e);

cout<<"\nThe scalar multiplication of 1 and 2 is "<<endl; //Scalar Multiplication

Matrix f = a.scalar(a,3);

f.printMatrix(f);

return 0;

}