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  1. #include <iostream>
  2. #include <vector>
  3. #include <numeric>
  4.  
  5. class hoge {
  6. public:
  7.   int *a;
  8.   int size;
  9.   hoge(int a[], int size) : a(a), size(size) {}
  10.   int sum() {
  11.     int s = 0;
  12.     for (int i = 0; i < size; i++)
  13.       s += a[i];
  14.     return s;
  15.   }
  16. };
  17.  
  18. template <class T>
  19. class hoge2 {
  20.   const std::vector<T>& a;
  21. public:
  22.   hoge2(const std::vector<T>& v) : a(v) {}
  23.   int sum() {
  24.     return std::accumulate(std::begin(a), std::end(a), 0);
  25.   }
  26. };
  27.  
  28. int main()
  29. {
  30.   std::vector<int> a = { 1, 2, 3 };
  31.   std::vector<int> a2 = a;
  32.  
  33.   hoge huga(&a2[0], a.size());
  34.   std::cout << huga.sum() << std::endl;
  35.   a2.push_back(4);
  36.   std::cout << huga.sum() << std::endl;
  37.  
  38.   a2 = a;
  39.  
  40.   hoge2<int> huga2(a2);
  41.   std::cout << huga2.sum() << std::endl;
  42.   a2.push_back(4);
  43.   std::cout << huga2.sum() << std::endl;
  44. }
  45.  
Success #stdin #stdout 0s 3468KB
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https://ideone.com/bdR6fU
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
secret

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