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  1. #include <iostream>
  2. #include <string>
  3. #include <stdexcept>
  4. #include <limits>
  5. using namespace std;
  6.  
  7. int main() {
  8. 	int num = 0;
  9. 	string s;
  10. 	size_t pos;
  11.  
  12. 	while (true){
  13. 		cout << "enter num: ";
  14. 		if (!(cin >> s)){
  15. 			cin.clear();
  16. 			cin.ignore(numeric_limits<streamsize>::max(), '\n');
  17. 			cout << "input error, try again" << endl;
  18. 		}
  19. 		else{
  20. 			try{
  21. 				num = stoi(s, &pos);
  22. 				if (pos != s.size()) throw invalid_argument("");
  23. 				if (num > 0){
  24. 					break;
  25. 				}
  26. 				cout << "num must be greater than 0" << endl;
  27. 			}
  28. 			catch (const exception &){
  29. 				cout << "num must be an int" << endl;
  30. 			}
  31. 		}
  32. 	}
  33.  
  34. 	cout << num;
  35. 	return 0;
  36. }
Success #stdin #stdout 0.01s 5328KB
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stdin
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0 0 a 1.0 1
stdout
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enter num: num must be greater than 0
enter num: num must be greater than 0
enter num: num must be an int
enter num: num must be an int
enter num: 1
https://ideone.com/KyMWXd
language:
C++ 4.3.2 (gcc-4.3.2)
created:
3 years ago
visibility:
public

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