Just playing with templates

matrix.cc

#include <stdexcept> // std::invalid_argument

#include <cstdio>  // printf() 
#include <cstdlib> // EXIT_SUCCESS
#include <cstring> // memset()

namespace NV
{

template<typename FloatType, unsigned w, unsigned h> class matrix
{
public:
    /**
     * @brief Initializes a matrix to empty values (0.0)
     */
    matrix() {
        memset(_m,0,w*h*sizeof(FloatType));
    }

    /**
     * @brief Simply print the matrix to stdout
     */
    inline void print() const {
        for(unsigned r = 0; r < h; r++) {
            for(unsigned c = 0; c < w; c++) {
                printf("%03.0f ",operator()(r,c));
            }
            putchar('\n');
        }
    }

    /**
     * @brief Get the element
     *
     * () was used instead of [] since [] can only hold one index
     *
     * @param r row
     * @param c column
     *
     * @return a concrete float
     */
    inline FloatType& operator()(unsigned r,unsigned c) {
        return _m[r][c];
    }

    /**
     * @brief Safer wrapper around operator()
     *
     * @param r See operator()
     * @param c See operator()
     *
     * @return same as (), but FLAOT_MIN for invalid values
     */
    inline FloatType& at(unsigned r, unsigned c) throw(std::invalid_argument) {
        if(r < w && c < h)
            return operator()(r,c);
        else
            throw std::invalid_argument("bad index");
    }

    
    /**
     * @brief Const version of operator()
     */
    inline FloatType operator()(unsigned r, unsigned c) const {
        return _m[r][c];
    }

private:
    /**
     * @brief Actual data. Note: This is NOT initialized by default!
     */
    FloatType _m[h][w];
};

// double matrix
template<unsigned w,unsigned h> class dmatrix : public matrix<double,w,h> {};

// float matrix
template<unsigned w,unsigned h> class fmatrix : public matrix<float,w,h>  {};

} // end namespace NV

int main(void)
{
    const unsigned size = 10;
    NV::dmatrix<size,size> m;

    for(unsigned i = 0; i < size; i++) {
        try {
            m.at(i,i)     = 321;
            m(i,size-i-1) = 123;
        } catch(std::invalid_argument& e) {
            printf("Got Exception: %s\n",e.what());
            break;
        }
    }
    m.print();
    return EXIT_SUCCESS;
}