MatricCommaInit.cpp

#include <iostream>
#include <ostream>
#include <string>
#include <vector>


class Matrix
{
    // Helper struct for comma initializer list insertion
    struct Matrix_CommaInitializer
    {
        Matrix_CommaInitializer(Matrix& m, size_t index)
            : matrix_(m)
            , index_(index)
            , range_(m.width_*m.height_) 
        {}
        
        Matrix_CommaInitializer& operator,(int i)
        {
            if(index_ >= range_) return *this;
            matrix_.vals_[index_/matrix_.width_][index_%matrix_.width_] = i;
            index_++;
            return *this;
        }
        
        Matrix& matrix_;
        unsigned index_;
        unsigned range_;
    };
    
public:
    Matrix(unsigned int w, unsigned int h)
        : width_(w)
        , height_(h)
        , vals_(height_, Matrix_Row(width_, 0))
    {}
    
    Matrix_CommaInitializer operator<<(int val)
    {
        return Matrix_CommaInitializer(*this, 0), val;
    }
    
    friend std::ostream& operator<<(std::ostream& os, const Matrix& m);
    
private:
    unsigned int width_;
    unsigned int height_;
    
    typedef std::vector<int> Matrix_Row;
    std::vector<Matrix_Row> vals_;
};

std::ostream& operator<<(std::ostream& os, const Matrix& m)
{
    os << "[\n";
    for(const Matrix::Matrix_Row& row : m.vals_)
    {
        os << "  [";
        for(int val : row)
        {
            os << val << ", ";   
        }
        os << "]\n";
    }
    os << "]";
    return os;
}


int main()
{
    Matrix m(3,2);
    
    m << 1, 2, 3, 4, 5;

    std::cout << "Matrix Contents: \n" << m << "\n";
    
    
    return 0;   
}