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  1. #include <iostream>
  2. #include <string>
  3. #include <utility>
  4. #include <cctype>
  5. using namespace std;
  6.  
  7. constexpr int brdsze = 8;	//Size of board
  8.  
  9. //Validate input and convert to co-ordinates
  10. //Returns true if OK and false if problem
  11. bool inpval(const string& inp, pair<int, int>& coord)
  12. {
  13. 	return (inp.size() == 2) && ((coord.first = toupper(inp[0]) - 'A') >= 0) && (coord.first < brdsze) && ((coord.second = inp[1] - '1') >= 0) && (coord.second < brdsze);
  14. }
  15.  
  16. int main()
  17. {
  18. 	//Offsets for knights possible moves - determines order of display
  19. 	constexpr int kgtpos = 8;
  20. 	constexpr pair<int, int> kgtmov[kgtpos] = { {-2, -1}, {-2, 1}, {-1, -2}, {-1, 2}, {1, -2}, {1, 2}, {2, -1}, {2, 1} };
  21.  
  22. 	string inp;
  23. 	pair<int, int> pos;
  24.  
  25. 	//Get and validate starting position
  26. 	do {
  27. 		cout << "Enter starting position: ";
  28. 		getline(cin, inp);
  29. 	} while (!inpval(inp, pos) && (cout << "\nInvalid starting position.\nInput format is CR where\nC is A to " << (char)('A' + brdsze - 1) << "\nR is 1 to " << brdsze << endl));
  30.  
  31. 	//Find last valid position
  32. 	int last = kgtpos - 1;
  33.  
  34. 	for (int got = false, rw, cl; !got; --last)
  35. 		got = ((cl = pos.first + kgtmov[last].first) >= 0) && (cl < brdsze) && ((rw = pos.second + kgtmov[last].second) >= 0) && (rw < brdsze);
  36.  
  37. 	cout << "\nAvailable positions from " << inp << " are" << endl;
  38.  
  39. 	//Find positions from first up to found last position and output in required format
  40. 	for (int pst = 0, first = 0, lst = last + 1, rw, cl; pst <= lst; ++pst)
  41. 		if (((cl = pos.first + kgtmov[pst].first) >= 0) && (cl < brdsze) && ((rw = pos.second + kgtmov[pst].second) >= 0) && (rw < brdsze))
  42. 			cout << (first++ ? ((pst == lst) ? ", and " : ", ") : "") << char(cl + 'A') << rw + 1;
  43.  
  44. 	cout << endl;
  45. }
  46.  
Success #stdin #stdout 0s 15240KB
comments (?)
stdin
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g1
stdout
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Enter starting position: 
Available positions from g1 are
E2, F3, and H3
https://ideone.com/n1YBkX
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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