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  1. #include <iostream>
  2. #include <string>
  3. using namespace std;
  4.  
  5. int main() {
  6. 	string str;
  7.  
  8. 	cin >> str;
  9.  
  10. 	string::const_iterator it = str.begin();
  11.  
  12. 	while(it != str.end() && isdigit(*it))
  13. 	{
  14. 		it++;
  15. 	}
  16.  
  17. 	if (!str.empty() && it == str.end())
  18. 		cout << "not a string";
  19. 	else
  20. 		cout << "valid";
  21.  
  22. 	return 0;
  23. }
Success #stdin #stdout 0s 3276KB
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stdin
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123
stdout
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not a string
https://ideone.com/gZkmQ0
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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