fork download
copy 
  1. #include <iostream>
  2. #include <sstream>
  3. #include <string>
  4.  
  5.     struct Text : std::string { using std::string::string; };
  6.  
  7.     std::istream& operator>>(std::istream& is, Text& t)
  8.     {
  9.         if (is.flags() & is.skipws) is >> std::skipws;
  10.         for (char c: t)
  11.         {
  12.             if (is.peek() != c)
  13.             {
  14.                 is.setstate(std::ios::failbit);
  15.                 break;
  16.             }
  17.             is.get();
  18.         }
  19.         return is;
  20.     }
  21.  
  22.     struct Until_Delim {
  23.     	Until_Delim(std::string& s, std::string delim) : s_(s), delim_(delim) { }
  24.     	std::string& s_;
  25.     	std::string delim_;
  26.     };
  27.  
  28.     std::istream& operator>>(std::istream& is, const Until_Delim& ud)
  29.     {
  30.         std::istream::sentry sentry(is);
  31.         size_t in_delim = 0;
  32.         for (char c = is.get(); is; c = is.get())
  33.         {
  34.             if (c == ud.delim_[in_delim])
  35.             {
  36.                 if (++in_delim == ud.delim_.size())
  37.                     break;
  38.                 continue;
  39.             }
  40.             else if (in_delim) // was part-way into delimiter match...
  41.             {
  42.                 ud.s_.append(ud.delim_, 0, in_delim);
  43.                 in_delim = 0;
  44.             }
  45.             ud.s_ += c;
  46.         }
  47.         // may need to trim trailing whitespace...
  48.         if (is.flags() & std::ios_base::skipws)
  49.             while (!ud.s_.empty() && std::isspace(ud.s_.back()))
  50.                 ud.s_.pop_back();
  51.         return is;
  52.     }
  53.  
  54.     int main()
  55.     {
  56.     	Text t{"ignore"};
  57.     	std::istringstream iss("ignore3.14ignore Some ignorable Text ignore 2.718");
  58.  
  59.     	double pi, e;
  60.     	std::string a_string;
  61.     	if (iss >> t >> pi >> t >> Until_Delim(a_string, "ignore") >> e)
  62.     	    std::cout << "pi " << pi << ", a_string '" << a_string << "', e " << e << '\n';
  63.     }
Success #stdin #stdout 0s 3460KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
pi 3.14, a_string 'Some ignorable Text', e 2.718
https://ideone.com/MpXNVd
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!