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  1. #include <iostream>
  2. #include <cmath>
  3.  
  4. class WrappedMatrix
  5. {
  6. public:
  7.     WrappedMatrix( int size ) : m_size(size)
  8.     {
  9.         m_data = new int*[size];
  10.         for ( int i = 0; i < size; ++i )
  11.         {
  12.             m_data[i] = new int[size];
  13.         }
  14.     }
  15.  
  16.     ~WrappedMatrix()
  17.     {
  18.         for ( int i = 0; i < m_size; ++i )
  19.         {
  20.             delete[] m_data[i];
  21.         }
  22.         delete[] m_data;
  23.     }
  24.  
  25.     inline int size() const { return m_size; }
  26.  
  27.     int** raw() { return m_data; }
  28.  
  29.     class Iterator
  30.     {
  31.     public:
  32.         Iterator( WrappedMatrix& base, int x, int y ) : m_base(base), m_x(x), m_y(y)
  33.         {
  34.         }
  35.  
  36.         int& operator*() { return m_base.raw()[m_x][m_y]; }
  37.  
  38.         Iterator& operator++()
  39.         {
  40.             if((++m_x == m_base.size() ) && (++m_y != m_base.size()))
  41.                 m_x = 0;
  42.  
  43.             return *this;   
  44.         }
  45.  
  46.         bool operator==( const Iterator &rhs ) { return m_x == rhs.m_x && m_y == rhs.m_y; }
  47.         bool operator!=( const Iterator &rhs ) { return m_x != rhs.m_x || m_y != rhs.m_y; }
  48.  
  49.     public:
  50.         WrappedMatrix& m_base;
  51.         int m_x, m_y;
  52.     };
  53.  
  54.     Iterator begin() { return Iterator( *this, 0, 0 ); }
  55.     Iterator end() { return Iterator( *this, m_size, m_size ); }
  56.  
  57.  
  58. private:
  59.     int m_size;
  60.     int** m_data;
  61. };
  62.  
  63. int f(int x)
  64. {
  65.     return x * x;
  66.     //return static_cast<int>( std::sin( static_cast<double>(x) / 1000.0 ) * 10000.0 );
  67. }
  68.  
  69. int main()
  70. {
  71.     //int size = 10000;
  72.     int size = 5000;
  73.     WrappedMatrix w1( size ), w2( size );
  74.  
  75.     // Initialise
  76.     std::cout << "Filling array" << std::endl;
  77.     for ( int x = 0; x < size; ++x )
  78.     {
  79.         for ( int y = 0; y < size; ++y )
  80.         {
  81.             w1.raw()[x][y] = x + y;
  82.         }
  83.     }
  84.  
  85.  
  86.     std::cout << "Calculating first loop" << std::endl;
  87.     //for ( int c = 0; c < 10; ++c )
  88.     {
  89.         if (1)
  90.         {
  91.             for ( int x = 0; x < size; ++x )
  92.             {
  93.                 for ( int y = 0; y < size; ++y )
  94.                 {
  95.                     w2.raw()[x][y] = f(w1.raw()[x][y]);
  96.                 }
  97.             }
  98.         }
  99.         else
  100.         {
  101.             WrappedMatrix::Iterator it1( w1.begin() ), it2( w2.begin() );
  102.  
  103.             while ( it1 != w1.end() )
  104.             {
  105.                 *it2 = f(*it1);
  106.                 //w2.raw()[it2.m_x][it2.m_y] = f(w1.raw()[it1.m_x][it1.m_y]);
  107.                 ++it1; ++it2;
  108.             }
  109.         }
  110.     }
  111.  
  112.  
  113.     return 0;
  114. }
  115.  
Success #stdin #stdout 0.25s 2812KB
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stdin
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Standard input is empty
stdout
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Filling array
Calculating first loop
https://ideone.com/bN6ln
language:
C++ (gcc 8.3)
created:
11 years ago
visibility:
public

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