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  1. #include "stdio.h"
  2.  
  3. namespace A {
  4.     template <typename T>
  5.     struct Key {
  6.       T value;
  7.     };
  8.  
  9.     template <
  10.         typename T,
  11.         template<typename> class KeyType
  12.     >
  13.     bool operator==(const KeyType<T> &a, const KeyType<T> &b) {
  14.       return a.value == b.value;
  15.     }
  16. }
  17. namespace B {
  18.     template <typename KT, typename VT>
  19.     struct MappedVal {
  20.       VT value;
  21.       KT key;
  22.     };
  23.  
  24.     template <
  25.         typename KT,
  26.         typename VT,
  27.         template<typename,typename> class MappedType
  28.     >
  29.     bool operator==(const MappedType<KT, VT> &a, const MappedType<KT, VT> &b) {
  30.       return (a.key == b.key && a.value == b.value);
  31.     }
  32. }
  33.  
  34. int main() {
  35.   A::Key<short> key1, key2;
  36.   key1.value = 1;
  37.   key2.value = 1;
  38.  
  39.   B::MappedVal<A::Key<short>, double> val1, val2;
  40.   val1.key = key1;
  41.   val1.value = 12.41;
  42.  
  43.   val2.key = key1;
  44.   val2.value = 12.41;
  45.  
  46.   bool test1 = (key1 == key2);
  47.   bool test2 = (val1 == val2);
  48.  
  49.   printf("key1 == key2: %s\n", (test1 ? "true" : "false"));
  50.   printf("val1 == val2: %s\n", (test2 ? "true" : "false"));
  51.  
  52.   return 0;
  53. }
  54.  
Success #stdin #stdout 0s 3340KB
comments (?)
stdin 
Standard input is empty
stdout 
key1 == key2: true
val1 == val2: true
https://ideone.com/rzOm5r
language:
C++ (gcc 8.3)
created:
12 years ago
visibility:
public

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