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  1. #include <iostream>
  2.  
  3. const unsigned dim = 3;
  4. typedef int array_type [dim][dim];
  5.  
  6. void average(array_type& dest, const array_type& src)
  7. {
  8.     // corners:
  9.     dest[  0  ][  0  ] = 
  10. 		(src[  0  ][  0  ] + src[  0  ][  1  ] + src[  1  ][  0  ] + src[  1  ][  1  ])/4;
  11.     dest[dim-1][  0  ] = 
  12. 		(src[dim-1][  0  ] + src[dim-2][  0  ] + src[dim-1][  1  ] + src[dim-2][  1  ])/4;
  13.     dest[  0  ][dim-1] = 
  14. 		(src[  0  ][dim-1] + src[  1  ][dim-1] + src[  0  ][dim-2] + src[  1  ][dim-2])/4;
  15.     dest[dim-1][dim-1] = 
  16. 		(src[dim-1][dim-1] + src[dim-2][dim-1] + src[dim-1][dim-2] + src[dim-2][dim-2])/4;
  17.  
  18.     // top, bottom, and sides:
  19.     for (unsigned i = 1; i < dim - 1; ++i)
  20.     {
  21.         const unsigned j = dim - 1;
  22.  
  23.         dest[0][i] = 
  24. 			(src[0][i-1] + src[0][i] + src[0][i+1] + src[ 1 ][i-1] + src[ 1 ][i] + src[ 1 ][i+1])/6;
  25.         dest[j][i] = 
  26. 			(src[j][i-1] + src[j][i] + src[j][i+1] + src[j-1][i-1] + src[j-1][i] + src[j-1][i+1])/6;
  27.  
  28.         dest[i][0] = 
  29. 			(src[i-1][0] + src[i][0] + src[i+1][0] + src[i-1][ 1 ] + src[i][ 1 ] + src[i+1][ 1 ])/6;
  30.         dest[i][j] = 
  31. 			(src[i-1][j] + src[i][j] + src[i+1][j] + src[i-1][j-1] + src[i][j-1] + src[i+1][j-1])/6;
  32.     }
  33.  
  34.     // middle:
  35.     for (unsigned i = 1; i < dim - 1; ++i)
  36.     {
  37.         for (unsigned j = 1; j < dim - 1; ++j)
  38.         {
  39.             dest[i][j] = (src[i-1][j-1] + src[i-1][j] + src[i-1][j+1] +
  40.                           src[ i ][j-1] + src[ i ][j] + src[ i ][j+1] +
  41.                           src[i+1][j-1] + src[i+1][j] + src[i+1][j+1]) / 9 ;
  42.         }
  43.     }
  44. }
  45.  
  46. void print(const array_type& array)
  47. {
  48.     for (unsigned i = 0; i < dim; ++i)
  49.     {
  50.         for (unsigned j = 0; j < dim; ++j)
  51.             std::cout << array[i][j];
  52.         std::cout << '\n';
  53.     }
  54.     std::cout << '\n';
  55. }
  56.  
  57. int main()
  58. {
  59.     array_type a = 
  60.     {
  61.         1, 2, 3,
  62.         4, 5, 6,
  63.         7, 8, 9
  64.     };
  65.  
  66.     array_type b = {};
  67.  
  68.     print(a);
  69.     print(b);
  70.  
  71.     average(b, a);
  72.     print(b);
  73. }
Success #stdin #stdout 0s 3340KB
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Standard input is empty
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123
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789

000
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000

334
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667
https://ideone.com/HPqtBf
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
secret

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