Map template class

Question

I am just confused as to what my file is supposed to look like. I am not sure on the syntax as well as how to read in the array.

Answer 1

I'm just confused as to what my Map.cpp file is supposed to look like.

• First of all, you can not write your template class implementation in a .cpp file. It should be all in a header file. Read the following for more info. Why can templates only be implemented in the header file?
• Secondly, there is no constructor declaration in your Map class which takes std::string as a parameter. Provide one!

  template <typename Domain, typename Range>
  class Map
  {
  public:  
   Map(const std::string& filename);  // declare one constructor which takes std::string
      // ... other members
  };
  

• Thirdly, your member function definitions missing the template parameters.

  template <typename Domain, typename Range>  // ---> this
  void Map<Domain, Range>::add(Domain d, Range r)
  {
   // implementation
  }
  
  template <typename Domain, typename Range>  // ---> this
  bool Map<Domain, Range>::lookup(Domain d, Range& r)
  {
   // implementation
  }
  

• Last but not the least, you are missing a proper destructor, which is essential for the Map class, as the allocated memory(using new) should be freed. Therefore, do accordingly the The rule of three/five/zero.

That being said, if you could have used std::vector, the manual memory management could be avoided.

#include <vector>

template <typename Domain, typename Range>
class Map
{
public:
    //...
private:
    // other members
    std::vector<Domain> dArray;
    std::vector<Range> rArray;
};

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As a side note, avoid practising with using namespace std;. Why is "using namespace std;" considered bad practice?