BasicsOfComputerSoftwareEngineering/OOP/05/Exercise02.cpp

#include <assert.h>
#include <iomanip>
#include <iostream>

class Matrix {
private:
    int rowSize, columnSize;
    int *content;

    friend std::ostream &operator<<(std::ostream &output, Matrix &mat);
    friend std::istream &operator>>(std::istream &input, Matrix &mat);
    friend Matrix& operator*(int lambda, Matrix& mat);

public:
    Matrix();
    Matrix(int newRowSize, int newColumSize);
    Matrix(Matrix &otherMat);
    ~Matrix();

    Matrix &operator*(Matrix &otherMatrix);
    Matrix &operator*(int lambda);
    int &operator()(int row, int column);
    Matrix &operator=(Matrix &otherMatrix);
    Matrix &operator+(Matrix &otherMatrix);
    bool operator==(Matrix &otherMatrix);

    int getRowSize();
    int getColumnSize();

    Matrix &transformation();
};

Matrix::Matrix() {
    this->rowSize = 0;
    this->columnSize = 0;
    this->content = NULL;
}

Matrix::Matrix(int newRowSize, int newColumnSize) {
    this->rowSize = newRowSize;
    this->columnSize = newColumnSize;
    this->content = new int[newRowSize * newColumnSize];
    for (int i = 0; i < newRowSize * newColumnSize; i++) {
        this->content[i] = 0;
    }
}

Matrix::Matrix(Matrix &otherMat) {
    this->rowSize = otherMat.getRowSize();
    this->columnSize = otherMat.getColumnSize();
    this->content = new int[this->rowSize * this->columnSize];
    for (int r = 0; r < this->rowSize; r++) {
        for (int c = 0; c < this->columnSize; c++) {
            (*this)(r, c) = otherMat(r, c);
        }
    }
}

Matrix::~Matrix() {
    delete[] this->content;
}

int &Matrix::operator()(int row, int column) {
    assert(row >= 0 && row < this->rowSize && column >= 0 &&
           column < this->columnSize);
    return this->content[row * this->columnSize + column];
}

Matrix &Matrix::operator*(Matrix &otherMatrix) {
    if (this->columnSize != otherMatrix.getRowSize()) {
        std::cout << "The size of these two matrix does not allow "
                     "multiplying. The matrix on the left has "
                  << this->columnSize
                  << " columns, whereas the matrix on the right has "
                  << otherMatrix.getRowSize() << " rows. " << std::endl;
        return *(new Matrix());
    }

    int resultRowSize = this->rowSize,
        resultColumnSize = otherMatrix.getColumnSize();
    Matrix *resultMat = new Matrix(resultRowSize, resultColumnSize);
    int tmpSum;
    for (int resultRow = 0; resultRow < resultRowSize; resultRow++) {
        for (int resultColumn = 0; resultColumn < resultColumnSize;
             resultColumn++) {
            tmpSum = 0;
            for (int p = 0; p < this->columnSize; p++) {
                tmpSum += (*this)(resultRow, p) * otherMatrix(p, resultColumn);
            }
            (*resultMat)(resultRow, resultColumn) = tmpSum;
        }
    }

    return *resultMat;
}

Matrix &Matrix::operator*(int lambda) {
    return lambda * (*this);
}

Matrix &Matrix::operator=(Matrix &otherMat) {
    if (NULL != this->content) {
        delete[] this->content;
    }
    this->rowSize = otherMat.getRowSize();
    this->columnSize = otherMat.getColumnSize();
    this->content = new int[this->rowSize * this->columnSize];
    for (int r = 0; r < this->rowSize; r++) {
        for (int c = 0; c < this->columnSize; c++) {
            (*this)(r, c) = otherMat(r, c);
        }
    }
    return (*this);
}

Matrix &Matrix::operator+(Matrix &otherMat) {
    if (this->rowSize != otherMat.getRowSize() ||
        this->columnSize != otherMat.getColumnSize()) {
        std::cout << "The size of these two does not allow adding. The matrix "
                     "on the left is "
                  << this->rowSize << "x" << this->columnSize
                  << " whereas the matrix on the right is "
                  << otherMat.getRowSize() << "x" << otherMat.getColumnSize()
                  << "." << std::endl;
        return *(new Matrix());
    }

    Matrix* result = new Matrix(*this);

    for (int r = 0; r < this->rowSize; r++) {
        for (int c = 0; c < this->columnSize; c++) {
            (*result)(r, c) += otherMat(r, c);
        }
    }
    return (*result);
}

bool Matrix::operator==(Matrix &otherMat) {
    if (this->rowSize != otherMat.getRowSize() ||
        this->columnSize != otherMat.getColumnSize()) {
        return false;
    }

    for (int r = 0; r < this->rowSize; r++) {
        for (int c = 0; c < this->columnSize; c++) {
            if ((*this)(r, c) != otherMat(r, c)) {
                return false;
            }
        }
    }
    return true;
}

int Matrix::getRowSize() {
    return this->rowSize;
}

int Matrix::getColumnSize() {
    return this->columnSize;
}

Matrix &Matrix::transformation() {
    Matrix *result = new Matrix(this->columnSize, this->rowSize);
    for (int r = 0; r < this->rowSize; r++) {
        for (int c = 0; c < this->columnSize; c++) {
            (*result)(c, r) = (*this)(r, c);
        }
    }
    return (*result);
}

std::ostream &operator<<(std::ostream &output, Matrix &mat) {
    output << "┌";
    for (int i = 0; i < mat.columnSize * 5 + 1; i++) {
        output << " ";
    }
    output << "┐" << std::endl;
    for (int r = 0; r < mat.rowSize; r++) {
        output << "│ ";
        for (int c = 0; c < mat.columnSize; c++) {
            output << std::setw(4) << std::setfill(' ') << mat(r, c) << " ";
        }
        output << "│" << std::endl;
    }

    output << "└";
    for (int i = 0; i < mat.columnSize * 5 + 1; i++) {
        output << " ";
    }
    output << "┘" << std::endl;
    return output;
}

std::istream &operator>>(std::istream &input, Matrix &mat) {
    std::cout << "Start input a " << mat.rowSize << "x" << mat.columnSize
              << " matrix:" << std::endl;
    for (int r = 0; r < mat.rowSize; r++) {
        for (int c = 0; c < mat.columnSize; c++) {
            std::cout << r << ", " << c << " (original: " << mat(r, c) << "): ";
            input >> mat(r, c);
        }
    }
    return input;
}

Matrix& operator*(int lambda, Matrix& mat) {
    Matrix* result = new Matrix(mat);
    for (int r = 0; r < mat.getRowSize(); r++) {
        for (int c = 0; c < mat.getColumnSize(); c++) {
            (*result)(r, c) *= lambda;
        }
    }
    return (*result);
}

int main() {
    int rowSize, columnSize;
    std::cout << "Input the size of the matrix: m x n" << std::endl;
    std::cin >> rowSize >> columnSize;
    Matrix a(rowSize, columnSize);
    Matrix b;
    std::cout << a << b;
    std::cin >> a;
    b = a.transformation();
    Matrix c = a * b;
    // clang-format off
    std::cout << "a =\n" << a
              << "b =\n" << b
              << "a * 3 =\n" << a * 3
              << "a * b =\n"<< a * b
              << "a * aT =\n" << a * a.transformation()
              << "a * a =\n" << a * a
              << "a * b == c: " << (a * b == c) << std::endl
              << "a == c: " << (a == c)
              << std::endl;
    // clang-format on
    return 0;
}