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  1. #include <iostream>
  2. #include <sstream>
  3. #include <limits>
  4. #include <cassert>
  5.  
  6. struct X { int a_, b_; };
  7.  
  8. std::istream& operator>>(std::istream& is, X& x)
  9. {
  10. 	char c;
  11. 	if (is >> x.a_ && is.get(c))
  12. 	    if (c == '\n')
  13. 	    {
  14. 	    	x.b_ = 1;
  15. 	        return is;
  16. 	    }
  17. 	    else if (c == '/' && is >> x.b_)
  18. 	        return is;
  19. 	    else
  20. 	        is.setstate(std::istream::failbit);
  21. 	return is;
  22. }
  23.  
  24. int main()
  25. {
  26. 	std::istringstream iss("5\n10/2\n3xyz\n8/17\n9\nNOWAY\n42/4\n");
  27. 	X x;
  28. 	while (iss >> x)
  29. 	    std::cout << "parsed " << x.a_ << '/' << x.b_ << '\n';
  30. 	iss.clear();
  31.  
  32. 	std::string remnants;
  33. 	assert(getline(iss, remnants));
  34. 	std::cout << "parsing failed, line remnants for '" << remnants << "'\n";
  35. 	// normally would prefer following to getline above...
  36. 	// iss.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
  37.  
  38. 	iss.exceptions(std::istream::failbit);
  39. 	while (iss)
  40. 	    try
  41. 	    {
  42.         	while (iss >> x)
  43. 	            std::cout << "also parsed " << x.a_ << '/' << x.b_ << '\n';
  44. 	    }
  45. 	    catch (const std::exception& e)
  46. 	    {
  47. 	    	std::cout << "caught exception " << e.what() << '\n';
  48. 	    	if (!iss.eof())
  49. 	    	{
  50. 	    	    iss.clear();
  51. 	            iss.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
  52. 	    	}
  53. 	    }
  54. 	std::cout << "eof " << iss.eof() << ", bad " << iss.bad()
  55. 	     << ", fail " << iss.fail() << '\n';
  56. }
Success #stdin #stdout 0s 3232KB
comments (?)
stdin
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Standard input is empty
stdout
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parsed 5/1
parsed 10/2
parsing failed, line remnants for 'yz'
also parsed 8/17
also parsed 9/1
caught exception basic_ios::clear
also parsed 42/4
caught exception basic_ios::clear
eof 1, bad 0, fail 1
https://ideone.com/0r7zJv
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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