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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. int wrap_orig(int index, int max) {
  5. 	if (index < 0)
  6.         return max - 1;
  7.     else if (index >= max)
  8.         return 0;
  9.     else
  10.         return index;
  11. }
  12.  
  13. size_t wrap_new(size_t index, size_t max, int delta) {
  14. 	if (delta >= 0)
  15.     {
  16.         unsigned absDelta = static_cast<unsigned>(delta);
  17.         if (absDelta >= max)
  18.             return 0;
  19.         else if (index >= max - absDelta)
  20.             return 0;
  21.         return index + absDelta;
  22.     }
  23.     size_t absDelta = static_cast<size_t>(-static_cast<ptrdiff_t>(delta));
  24.     if (index >= absDelta)
  25.         return index - absDelta;
  26.     else if (max == 0)
  27.         return 0;
  28.     return max - 1;
  29. }
  30.  
  31. int main() {
  32. 	cout << wrap_orig(10 + -2, 0) << "\n";
  33. 	cout << wrap_new(10, 0, -2)   << "\n";
  34. 	cout << "\n";
  35. 	cout << wrap_orig(10 + -2, 2) << "\n";
  36. 	cout << wrap_new(10, 2, -2)   << "\n";
  37. 	cout << "\n";
  38. 	cout << wrap_orig(10 + -2, 10) << "\n";
  39. 	cout << wrap_new(10, 10, -2)   << "\n";
  40. 	cout << "\n";
  41. 	cout << wrap_orig(10 + -2, 15) << "\n";
  42. 	cout << wrap_new(10, 15, -2)   << "\n";
  43. 	cout << "\n";
  44. 	return 0;
  45. }
Success #stdin #stdout 0.01s 5316KB
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https://ideone.com/RP6iOP
language:
C++ (gcc 8.3)
created:
17 hours ago
visibility:
secret

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