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  1. #include <iostream>
  2. #include <sstream>
  3.  
  4. enum class dna_strand : char {
  5.     positive = '+',
  6.     negative = '-'
  7. };
  8.  
  9. std::ostream& operator <<(std::ostream& out, dna_strand strand) {
  10.     return out << static_cast<char>(strand);
  11. }
  12.  
  13. std::istream& operator >>(std::istream& in, dna_strand& strand) {
  14.     char ch{};
  15.     if (not in >> ch)
  16.         return in;
  17.     if (ch == '+')
  18.         strand = dna_strand::positive;
  19.     else if (ch == '-')
  20.         strand = dna_strand::negative;
  21.     else
  22.         in.setstate(std::ios::failbit);
  23.     return in;
  24. }
  25.  
  26. int main() {
  27.     std::stringstream sstr("+");
  28.     dna_strand s{};
  29.     sstr >> s;
  30.     std::cout << "\"" << s << "\"\n";
  31. }
Success #stdin #stdout 0s 3064KB
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""
https://ideone.com/u8hg2A
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
public

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