TwoDimArray

twodimarr.cpp

#include <chrono>
#include <cstring>
#include <iostream>
#include <vector>
using namespace std;

class TwoDimArray {
    double *data;
    size_t nrows, ncols;
public:
    TwoDimArray() : data(nullptr), nrows(0), ncols(0) {}
    TwoDimArray(size_t nrows, size_t ncols) : nrows(nrows), ncols(ncols) {
        data = new double[nrows * ncols];
        memset(data, 0, nrows * ncols * sizeof(double));
    }
    ~TwoDimArray() { delete[] data; }
    class Row {
        friend class TwoDimArray;
        double* p;
        size_t n;
        Row(double *p, size_t n) : p(p), n(n) {}
    public:
        double  operator[](size_t idx) const { /*контроль*/ return p[idx]; }
        double& operator[](size_t idx)       { /*контроль*/ return p[idx]; }
    };

    double  value(size_t row, size_t col) const { return data[row*ncols + col]; }
    double& value(size_t row, size_t col)       { return data[row*ncols + col]; }
    double  operator()(size_t row, size_t col) const { return data[row*ncols + col]; }
    double& operator()(size_t row, size_t col)       { return data[row*ncols + col]; }
    const Row operator[](size_t row) const { return Row(data + (ncols * row), ncols); }
          Row operator[](size_t row)       { return Row(data + (ncols * row), ncols); }
    size_t cols() const { return ncols; }
    size_t rows() const { return nrows; }
};

class TwoDimArray2 {
    vector<vector<double>> data;
public:
    TwoDimArray2() {}
    TwoDimArray2(size_t nrows, size_t ncols) : data(nrows, vector<double>(ncols, 0.0)) {}
    ~TwoDimArray2() { }
    double  value(size_t row, size_t col) const { return data[row][col]; }
    double& value(size_t row, size_t col)       { return data[row][col]; }
    double  operator()(size_t row, size_t col) const { return data[row][col]; }
    double& operator()(size_t row, size_t col)       { return data[row][col]; }
    const vector<double>& operator[](size_t row) const { return data[row]; }
          vector<double>& operator[](size_t row)       { return data[row]; }
    size_t cols() const { return data.empty() ? 0 : data[0].size(); }
    size_t rows() const { return data.size(); }
};

/// Написать код, сравнивающий производительность обоих решений
/// Должен работать минимум 30с каждый

int main() {
    chrono::high_resolution_clock clock;
    auto start = clock.now();
    TwoDimArray arr(5, 4);
    arr.value(2, 2) = 5;
    arr(3, 4) = 2;
    arr[3][1] = 7;
    auto end = clock.now();
    auto d = end - start;
    cout << "we worked for " << d.count() << " seconds" << endl;

    for (size_t i = 0; i < arr.rows(); i++) {
        for (size_t j = 0; j < arr.cols(); j++) {
            if (j)
                cout << '\t';
            cout << arr.value(i, j);
        }
        cout << endl;
    }
    return 0;
}