CODEWITHSUNDEEP
c++c++11
oxidising
oxidising

Reputation: 310

Outputting member type of a vector of types

I have a vector of unique_ptr<my_class> and would like to be able to pass to a function the member variable of this class I'd like to output. This vector is part of a class in itself.

For example I would like to 

void my_top_class::output_member(sometype var_to_output, std::ofstream &out)
{
   // Iterate over the vector and output the member variable
   out << my_class->var_to_output << std::endl;
   // Or something similar
}

And then just do 

 my_top_class.output_member(var1, file_out);
 my_top_class.output_member(var2, file_out);

At the moment I have a separate function for each member variable and this feels cumbersome

Upvotes: 1

Views: 69

Answers (2)

Constructor
Constructor

Reputation: 7491

Use pointer to data members (it is only an example, you should adopt it to your situation):

template <typename MemberType>
void output_member(const MyClass& my_object, MemberType MyClass::* var_to_output)
{
    std::cout << my_object.*var_to_output << std::endl;
}

Here .* is one of pointer to member access operators.

Example of using:

struct MyClass
{
    int member_variable_;
};

// ...

MyClass my_object{42};

output_member(my_object, &MyClass::member_variable_);

Live demo

Upvotes: 2

MindRoller
MindRoller

Reputation: 241

Maybe just create a new class that you will use to store your elemets? Like this:

class Memory 
{
   private:
std::vector<yourclass> vec;

public:
std::vector<yourclass> getVector()
{
return vec;
}
};

Then create an object of that class in your main class main window, whatever you are using. Actually you didn't provide too much information and it is hard to answer your question.

Upvotes: 0

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