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  1. #include <iostream>
  2. #include <math.h> //log10(), floor()
  3.  
  4. int main()
  5. {
  6.     int num, holder;
  7.     int count = 1;
  8.  
  9.     std::cin >> num;
  10.     const int n = num > 0 ? num : -num;
  11.     int spiral[n][n];
  12.     int spaces = log10(n*n)+2; //stolen from /u/J354
  13.  
  14.     for (int d = 0; d < n/2 + n%2; d++)
  15.     { //Constructs the spiral one layer at a time
  16.         for (int c = d; c < n-d-1; c++)
  17.         { //Constructs the four sides of the layer
  18.             spiral[d][c] = count;
  19.             spiral[c][n-1-d] = (n-1-2*d) + count;
  20.             spiral[n-1-d][n-1-c] = 2*(n-1-2*d) + count;
  21.             spiral[n-1-c][d] = 3*(n-1-2*d) + count;
  22.             count++;
  23.         }
  24.         count += 3*(n-1-2*d);
  25.     }
  26.     //Dirty fix for odd n
  27.     if (n%2) {spiral[n/2][n/2] = n*n;}
  28.  
  29.     if (num < 0)
  30.     { //Flip if negative input
  31.         for (int i = 0; i < n; i++)
  32.         {
  33.             for (int j = i; j < n; j++)
  34.             {
  35.                 holder = spiral[i][j];
  36.                 spiral[i][j] = spiral[j][i];
  37.                 spiral[j][i] = holder;
  38.             }
  39.         }
  40.     }
  41.  
  42.     for (int i = 0; i < n; i++)
  43.     { //Print output
  44.         for (int j = 0; j < n; j++)
  45.         {
  46.             for (int s = spaces-floor(log10(spiral[i][j]))-1; s > 0; s--) {std::cout << " ";}
  47.             std::cout << spiral[i][j];            
  48.             if (j == n-1) {std::cout << "\n";}
  49.         }
  50.     }
  51.  
  52.     return 0;
  53. }
Success #stdin #stdout 0s 15240KB
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  1  2  3  4
 12 13 14  5
 11 16 15  6
 10  9  8  7
https://ideone.com/5fAB79
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
public

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