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  1. #include <iostream>
  2.  
  3. bool is_number(char const * s) {
  4. 	if (!s || !*s) 
  5. 		return false;	// нуллптр и пустая строка не число нихуя!
  6.  
  7. 	while (*s >= '0' && *s <= '9')
  8. 		++s;
  9.  
  10. 	return !*s;
  11. }
  12.  
  13. int main() {
  14. 	std::cout << std::boolalpha
  15. 		<< is_number("625462345") << std::endl
  16. 		<< is_number("625f62345") << std::endl
  17. 		<< is_number("") << std::endl
  18. 		<< is_number("000000000000000") << std::endl
  19. 		<< is_number(NULL) << std::endl;
  20. 	return 0;
  21. }
Success #stdin #stdout 0s 4280KB
comments (?)
stdin
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Standard input is empty
stdout
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true
false
false
true
false
https://ideone.com/3tyvcw
language:
C++ (gcc 8.3)
created:
3 years ago
visibility:
public

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