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  1. #include <vector>
  2. #include <algorithm>
  3. #include <type_traits>
  4.  
  5. template<typename T> class Row;
  6. template<typename T> class ConstRow;
  7.  
  8. template<typename T>
  9. class Matrix2D
  10. {
  11.    // Matrix aus bool nicht erlauben
  12.    static_assert( !std::is_same<bool,T>::value, "T must not be bool because of std::vector<bool> anomaly" );
  13.  
  14. public:
  15.    using value_type      = T;
  16.    using reference       = T&;
  17.    using const_reference = T const&;
  18.    using pointer         = T*;
  19.    using const_pointer   = T const*;
  20.    using size_type       = std::size_t;
  21.    using difference_type = std::ptrdiff_t;
  22.    using row_type        = Row<T>;
  23.    using const_row_type  = ConstRow<T>;
  24.  
  25. private:
  26.    std::vector<T> Elements_;
  27.    size_type      Rows_ = 0;
  28.    size_type      Cols_ = 0;
  29.  
  30. public:
  31.    Matrix2D() = default;
  32.    Matrix2D( size_type rows, size_type cols ) :
  33.       Matrix2D( rows, cols, value_type() )
  34.    {
  35.    }
  36.  
  37.    Matrix2D(size_type rows, size_type cols, const_reference v ) :
  38.       Elements_( rows * cols, v ),
  39.       Rows_( rows ),
  40.       Cols_( cols )
  41.    {
  42.    }
  43.  
  44.    row_type operator[]( size_type index )
  45.    {
  46.       pointer beg = Elements_.data() + index * Cols_; 
  47.       return row_type( beg, beg + Cols_ );
  48.    }
  49.  
  50.    const_row_type operator[]( size_type index ) const
  51.    {
  52.        const_pointer beg = Elements_.data() + index * Cols_; 
  53.        return const_row_type( beg, beg + Cols_ );
  54.     }
  55. };
  56.  
  57. template<typename T>
  58. class Row
  59. {
  60.    T* Begin_= nullptr;
  61.    T* End_  = nullptr;
  62.  
  63. public:
  64.    Row( T* beg, T* end ) :
  65.       Begin_( beg ),
  66.       End_( end )
  67.    {
  68.    }
  69.  
  70.    bool empty() const
  71.    {
  72.       return Begin_ == End_;
  73.    }
  74.  
  75.    std::size_t size() const
  76.    {
  77.       return std::distance( begin(), end() );
  78.    }
  79.  
  80.    T& operator[]( std::size_t index )
  81.    {
  82.       return Begin_[index];
  83.    }
  84.  
  85.    T const& operator[]( std::size_t index ) const
  86.    {
  87.       return Begin_[index];
  88.    }
  89.  
  90.    T* begin()
  91.    {
  92.       return Begin_;
  93.    }
  94.  
  95.    T* end()
  96.    {
  97.       return End_;
  98.    }
  99.  
  100.    T const* begin() const
  101.    {
  102.       return Begin_;
  103.    }
  104.  
  105.    T const* end() const
  106.    {
  107.       return End_;
  108.    }
  109. };
  110.  
  111. template<typename T>
  112. class ConstRow
  113. {
  114.    T const* Begin_ = nullptr;
  115.    T const* End_   = nullptr;
  116.  
  117. public:
  118.    ConstRow( T const* beg, T const* end ) :
  119.       Begin_( beg ),
  120.       End_( end )
  121.    {
  122.    }
  123.  
  124.    ConstRow( Row<T> const& r ) :
  125.       Begin_( r.begin() ),
  126.       End_( r.end() )
  127.    {
  128.    }
  129.  
  130.    T const& operator[]( std::size_t index ) const
  131.    {
  132.       return Begin_[index];
  133.    }
  134. };
  135.  
  136. int main()
  137. {
  138.    Matrix2D<int> m( 2, 2,-1 );
  139.    m[0][0] = 1;
  140. }
Success #stdin #stdout 0s 5500KB
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https://ideone.com/XVurMN
language:
C++ (gcc 8.3)
created:
2 years ago
visibility:
public

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