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  1. #include <type_traits>
  2. #include <string>
  3. #include <iostream>
  4.  
  5. using namespace std;
  6.  
  7. void testString(string value) {
  8.     cout << "A string: " << value << endl;
  9. }
  10.  
  11. void testInt(int value) {
  12.     cout << "An int: " << value << endl;
  13. }
  14.  
  15. template <typename U>
  16. void testOther(U value) {
  17.     cout << "Unknown type: " << value << endl;
  18. }
  19.  
  20. template <typename T>
  21. class Test {
  22. public:
  23.  
  24.     constexpr Test(T value) : value(value) {}
  25.  
  26.     void test() {
  27.         if (is_same<T, string>::value) {
  28.             string &_value = (*reinterpret_cast<string *>(&value));
  29.             testString(_value);
  30.         } else if (is_same<T, int>::value) {
  31.             int &_value = (*reinterpret_cast<int *>(&value));
  32.             testInt(_value);
  33.         } else {
  34.             testOther(value);
  35.         }
  36.     }
  37.  
  38. private:
  39.  
  40.     T value;
  41. };
  42.  
  43. int main() {
  44.     Test<string>("Hello, world!").test();
  45.     Test<int>(42).test();
  46.     Test<float>(42.1).test();
  47. }
Success #stdin #stdout 0s 3032KB
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stdin
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Standard input is empty
stdout
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A string: Hello, world!
An int: 42
Unknown type: 42.1
https://ideone.com/v1KmTA
language:
C++14 (gcc 8.3)
created:
13 years ago
visibility:
public

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