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  1. #include <limits>
  2. #include <utility>
  3. #include <iostream>
  4.  
  5. template <typename T>
  6. struct is_integral {
  7.   static bool const value = std::numeric_limits<T>::is_integer;
  8. };
  9.  
  10. template <typename T>
  11. struct is_real {
  12.   static bool const value = not is_integral<T>::value;
  13. };
  14.  
  15. template <typename T, typename L, typename R>
  16. struct are_all_integral {
  17.   static bool const value = is_integral<T>::value and
  18.                             is_integral<L>::value and
  19.                             is_integral<R>::value;
  20. };
  21.  
  22. template <typename T, typename L, typename R>
  23. struct is_any_real {
  24.   static bool const value = is_real<T>::value or
  25.                             is_real<L>::value or
  26.                             is_real<R>::value;
  27. };
  28.  
  29.  
  30. template <typename T, typename L, typename R>
  31. typename std::enable_if<are_all_integral<T, L, R>::value, bool>::type
  32. inRange(T x, L start, R end) {
  33.   typedef typename std::common_type<T, L, R>::type common;
  34.   std::cout << "  inRange(" << x << ", " << start << ", " << end << ") -> Integral\n";
  35.   return static_cast<common>(x) >= static_cast<common>(start) and
  36.          static_cast<common>(x) <= static_cast<common>(end);
  37. }
  38.  
  39. template <typename T, typename L, typename R>
  40. typename std::enable_if<is_any_real<T, L, R>::value, bool>::type
  41. inRange(T x, L start, R end) {
  42.   typedef typename std::common_type<T, L, R>::type common;
  43.   std::cout << "  inRange(" << x << ", " << start << ", " << end << ") -> Real\n";
  44.   return static_cast<common>(x) >= static_cast<common>(start) and
  45.          static_cast<common>(x) <= static_cast<common>(end);
  46. }
  47.  
  48. int main() {
  49.   std::cout << "Pure cases\n";
  50.   inRange(1, 2, 3);
  51.   inRange(1.5, 2.5, 3.5);
  52.  
  53.   std::cout << "Mixed int/unsigned\n";
  54.   inRange(1u, 2, 3);
  55.   inRange(1, 2u, 3);
  56.   inRange(1, 2, 3u);
  57.  
  58.   std::cout << "Mixed float/double\n";
  59.   inRange(1.5f, 2.5, 3.5);
  60.   inRange(1.5, 2.5f, 3.5);
  61.   inRange(1.5, 2.5, 3.5f);
  62.  
  63.   std::cout << "Mixed int/double\n";
  64.   inRange(1.5, 2, 3);
  65.   inRange(1, 2.5, 3);
  66.   inRange(1, 2, 3.5);
  67.  
  68.   std::cout << "Mixed int/double, with more doubles\n";
  69.   inRange(1.5, 2.5, 3);
  70.   inRange(1.5, 2, 3.5);
  71.   inRange(1, 2.5, 3.5);
  72. }
Success #stdin #stdout 0s 2832KB
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Standard input is empty
stdout
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Pure cases
  inRange(1, 2, 3) -> Integral
  inRange(1.5, 2.5, 3.5) -> Real
Mixed int/unsigned
  inRange(1, 2, 3) -> Integral
  inRange(1, 2, 3) -> Integral
  inRange(1, 2, 3) -> Integral
Mixed float/double
  inRange(1.5, 2.5, 3.5) -> Real
  inRange(1.5, 2.5, 3.5) -> Real
  inRange(1.5, 2.5, 3.5) -> Real
Mixed int/double
  inRange(1.5, 2, 3) -> Real
  inRange(1, 2.5, 3) -> Real
  inRange(1, 2, 3.5) -> Real
Mixed int/double, with more doubles
  inRange(1.5, 2.5, 3) -> Real
  inRange(1.5, 2, 3.5) -> Real
  inRange(1, 2.5, 3.5) -> Real
https://ideone.com/NXPuG
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
public

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