Memory leak C++ string

Question

I have a class eg

class test{

   public:
      somedatahere
      test();
     ~test();
   private:
       string mystring;

}

In this class the constructor reads the contents of a file in variable mystring.My question is :

Does mystring gets freed when the class destructs or I must free it manually? How can I free mystring ?

Answer 1

Since mystring is part of the object, it will go out of scope when the object does. There's no need to "manually" free it, and indeed you can't.

This would be different if mystring was a pointer to memory allocated with new (or new[]), then you'd have to manually delete (or delete[]) it from your destructor.

Answer 2

You only have to free what you allocate. new should be matched by delete, and new[] matched by delete[].

If you don't do either, then a well-behaved class shouldn't require you to do the other. And yes, the standard library is well-behaved.

So no, you don't need to do anything. Let the std::string instance clean up after itself. (And of course, follow its example, and ensure that your own classes do the same)