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  1. #include <string>
  2. #include <iostream>
  3. #include <sstream>
  4. #include <stdexcept>
  5.  
  6. int gcd(int a, int b)
  7. {
  8.     a = std::abs(a);
  9.     b = std::abs(b);
  10.  
  11.     while (a)
  12.     {
  13.         int temp = a;
  14.         a = b % a;
  15.         b = temp;
  16.     }
  17.  
  18.     return b;
  19. }
  20.  
  21. struct Rational
  22. {
  23.     Rational(std::string);
  24.     friend std::ostream& operator<<(std::ostream&, const Rational&);
  25.  
  26. private:
  27.     void reduce();
  28.  
  29.     std::string equation;
  30.     int numerator;
  31.     int denominator;
  32. };
  33.  
  34. void Rational::reduce()
  35. {
  36.     int divisor = gcd(numerator, denominator);
  37.     numerator /= divisor;
  38.     denominator /= divisor;
  39. }
  40.  
  41. Rational::Rational(std::string inputString) : equation(inputString)
  42. {
  43.     std::istringstream in(inputString);
  44.  
  45.     char dummy;
  46.     if (!(in >> numerator) || !(in >> dummy) || !(in >> denominator))
  47.         throw std::invalid_argument("ERROR: Invalid argument - \"" + inputString + '"');
  48.  
  49.     if (denominator == 0)
  50.         throw std::domain_error("ERROR: Denominator cannot be 0 - \"" + inputString + '"');
  51.  
  52.     reduce();
  53. }
  54.  
  55. std::ostream& operator<<(std::ostream& os, const Rational& r)
  56. {
  57.     os << r.numerator;
  58.  
  59.     if (r.denominator != 1)
  60.         os << " / " << r.denominator;
  61.  
  62.     return os;
  63. }
  64.  
  65. int main()
  66. {
  67.     std::string line;
  68.     while (std::getline(std::cin, line) && line.size())
  69.     {
  70.         try {
  71.             std::cout << Rational(line) << '\n';
  72.         }
  73.  
  74.         catch (std::exception& ex)
  75.         {
  76.             std::cout << ex.what() << '\n';
  77.         }
  78.  
  79.         std::cout << '\n';
  80.     }
  81. }
Success #stdin #stdout 0s 3484KB
comments (?)
stdin
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9/3
8/10
abcd
100/0
stdout
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3

4 / 5

ERROR: Invalid argument - "abcd"

ERROR: Denominator cannot be 0 - "100/0"
https://ideone.com/B7Nm0X
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
secret

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