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  1. #include <ctime>
  2. #include <iostream>
  3. #include <sstream>
  4. #include <string>
  5. #include <iomanip>
  6. #include <utility>
  7.  
  8. struct make_string
  9. {
  10.     make_string & operator<<(std::ostream& (*manip)(std::ostream&))
  11.     {
  12.         manip(ostr);
  13.         return *this;
  14.     }
  15.  
  16.     template <typename T> make_string & operator<<(const T & t)
  17.     {
  18.         ostr << t;
  19.         return *this;
  20.     }
  21.  
  22.     operator std::string() const { return ostr.str(); }
  23.  
  24.     std::string str() const { return ostr.str(); }
  25.  
  26.     std::ostringstream ostr;
  27. };
  28.  
  29.  
  30. void message(const std::string&) {}
  31.  
  32. int main()
  33. {
  34.     message(make_string() << "1 + 1 = " << 2 << "\n"); // OK
  35.     message(make_string() << "1 + 1 = " << 2 << std::endl); // Not OK
  36.  
  37.  
  38.     // OK
  39.     std::ostringstream os;
  40.     os << std::endl;
  41.  
  42.     // Not ok.
  43.     make_string mk;
  44.     mk << std::endl;
  45. }
Success #stdin #stdout 0s 3064KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/3k0r9I
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
public

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