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  1. #include <iostream>
  2. #include <tuple>
  3. template<typename T> struct FunctionSignatureParser; // Must declare a primary template with a missing implementation
  4. template<typename Result, typename...Args> struct FunctionSignatureParser<Result(Args...)>
  5. {
  6. 	using return_type = Result;
  7. 	using args_tuple = std::tuple<Args...>;
  8. 	template <size_t i> struct arg
  9. 	{
  10. 		typedef typename std::tuple_element<i, args_tuple>::type type;
  11. 	};
  12. };
  13. short square(char x) { // 8-bit integer as input, 16-bit integer as output
  14.     return short(x)*short(x);
  15. }
  16. int main() {
  17.         char answer = 42;
  18.         static_assert(std::is_same<char, FunctionSignatureParser<decltype(square)>::arg<0>::type>::value, "Function 'square' does not use an argument of type 'char'");
  19.         static_assert(std::is_same<short, FunctionSignatureParser<decltype(square)>::return_type>::value, "Function 'square' does not return a value of type 'short'");
  20.         short sqrAnswer = square(answer);
  21.         std::cout << "The square of " << +answer << " is " << +sqrAnswer << std::endl;
  22.         return 0;
  23. }
Success #stdin #stdout 0s 4460KB
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stdin
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Standard input is empty
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The square of 42 is 1764
https://ideone.com/6JV52t
language:
C++ (gcc 8.3)
created:
7 years ago
visibility:
public

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