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  1. #include <string>
  2. #include <memory>
  3. #include <vector>
  4.  
  5. class PacketData{
  6.     struct Context {
  7.         virtual ~Context() = default;
  8.     };
  9.     template<typename T>
  10.     struct Instance : Context {
  11.         Instance(T&& t):data_{std::move(t)}{
  12.  
  13.         }
  14.         T data_;
  15.     };
  16.     std::unique_ptr<Context> self_;
  17.     public:
  18.     template<typename T>
  19.     PacketData(T in):self_{new Instance<T>{std::move(in)}}{}
  20.     //move is easy, copy is harder ;)
  21.  
  22.     template<typename T>
  23.     bool isA(){
  24.         return dynamic_cast<Instance<T>*>(self_.get()) != nullptr;
  25.     }
  26.     template<typename T>
  27.     T& asA(){
  28.         if(!isA<T>()){
  29.             throw std::runtime_error("bad cast or something");
  30.         }
  31.         return dynamic_cast<Instance<T>*>(self_.get())->data_;
  32.     }
  33. };
  34.  
  35. using Packet = std::vector<PacketData>;
  36.  
  37. int main() {
  38. 	Packet packet;
  39. 	packet.push_back(4);
  40. 	packet.push_back(4.4f);
  41. 	packet.push_back(std::string{"test"});
  42. 	int i = packet[0].asA<int>();
  43. 	float f = packet[1].asA<float>();
  44. 	std::string s = packet[2].asA<std::string>();
  45. 	return 0;
  46. }
Success #stdin #stdout 0s 3472KB
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stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/U7rmOL
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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