Answer to Question #218811 in C++ for Hemambar

Question

create a class Matrix the stores it in a safe 2D array .that is it it should check for array index bounds .a constructor should allow the programmer to specify the actual dimensions of the matrix. define number functions : putel() for taking 3 argument row index , column index and the element storing it in the corresponding location. getel() for taking 2 arguments row and column indexes and returns the elements from that location . overload the operators +,-,and * appropriately

Answer 1

#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <ctime>


using namespace std;


class Matrix {


private:
	double *array2D;
	int rows;
	int columns;
public:
	Matrix(int nRows, int nCols){
		rows = nRows>0 ? nRows : 1;
		columns = nCols>0 ? nCols : 1;
		array2D = new double[nRows*nCols];
	}
	Matrix::~Matrix()
	{
		delete [] array2D;
	}
	void putel(int selectedRow, int selectedColumn, double element) {
		if (selectedRow <0 || selectedRow >= rows) {
			selectedRow = 0;
		}
		if (selectedColumn < 0  || selectedColumn >= columns) {
			selectedColumn = 0;
		}
		array2D[selectedRow*columns + selectedColumn] = element;
	}
	double getel(int selectedRow, int selectedColumn){
		if (selectedRow <0 || selectedRow >= rows) {
			selectedRow = 0;
		}
		if (selectedColumn < 0  || selectedColumn >= columns) {
			selectedColumn = 0;
		}
		return array2D[selectedRow*columns + selectedColumn];
	}
	Matrix* operator+(Matrix& otherMatrix) 
	{
		if (rows != otherMatrix.rows || columns != otherMatrix.columns) {
			cout << "Wrong matrix dimention.\n";
			return NULL;
		}
		Matrix* matrixResult=new Matrix(rows, columns);
		for (int i=0; i<rows*columns; i++) {
			matrixResult->array2D[i] = array2D[i] + otherMatrix.array2D[i];
		}
		return matrixResult;
	}
	Matrix* operator-(Matrix& otherMatrix){
		if (rows != otherMatrix.rows || columns != otherMatrix.columns) {
			cout << "Wrong matrix dimention.\n";
			return NULL;
		}
		Matrix* matrixResult=new Matrix(rows, columns);
		for (int i=0; i<rows*columns; i++) {
			matrixResult->array2D[i] = array2D[i] - otherMatrix.array2D[i];
		}
		return matrixResult;
	}
	Matrix* operator*(Matrix& other)
	{
		if (columns != other.rows) {
			cout << "Wrong matrix dimention.\n";
			return NULL;
		}
		Matrix* matrixResult=new Matrix(rows,other.columns);
		for (int i=0; i<rows; i++) {
			for(int j=0; j<other.columns; j++) {
				double sum = 0.0;
				for (int k=0; k<columns; k++) {
					sum += getel(i, k) * other.getel(k, j);
				}
				matrixResult->putel(i, j, sum);
			}
		}
		return matrixResult;
	}


	void display()
	{
		for (int i=0; i<rows; i++) {
			for (int j=0; j<columns; j++) {
				cout<< setw(3) << getel(i, j) << " ";
			}
			cout<< endl;
		}
	}


};






int main() {
	srand(time(nullptr));
	Matrix* matrix1=new Matrix(4, 6);
	Matrix* matrix2=new Matrix(4, 6);
	Matrix* matrix3=new Matrix(6, 4);


	for (int i=0; i<4; i++) {
		for (int j=0; j<6; j++) {
			matrix1->putel(i, j, (rand() % 10));
			matrix2->putel(i, j,(rand() % 10));
			matrix3->putel(j, i,(rand() % 10));
		}
	}
	cout << "Matrix 1:\n";
	matrix1->display();
	cout << "\nMatrix 2:\n";
	matrix2->display();
	cout << "\nMatrix 3:\n";
	matrix3->display();
	Matrix* matrixResult=((*matrix1)+(*matrix2));
	cout << "\nMatrix 1 + Matrix 2:\n";
	matrixResult->display();
	cout << "\nMatrix 1 - Matrix 2:\n";
	matrixResult=((*matrix1)-(*matrix2));
	matrixResult->display();
	cout << "\nMatrix 1 * Matrix 3:\n";
	matrixResult=((*matrix1)*(*matrix3));
	matrixResult->display();
	


	delete matrix1;
	delete matrix2;
	delete matrix3;
	delete matrixResult;


	int pause;
	cin>>pause;


	return 0;
}