The first constructor in the header should not end with a semicolon. #include <string> is missing in the header. string is not qualified with std:: in the .cpp file. Those are all simple syntax errors. More importantly: you are not using references, when you should. Also the way you use the ifstream is broken. I suggest learning C++ before trying to use it. … Read more
Your problem with the first version is that your compiler is trying to prevent a bug. Your problem with the second version is that you outsmarted your compiler and successfully managed to create a bug. Given your constructor, you want to store pointers to the float values that are passed by reference. Since your second … Read more
You use standard syntax (using this like a method) to pick the overload, inside the class: then: Note also: you can chain to constructors on the base-type using base(…) you can put extra code into each constructor the default (if you don’t specify anything) is base() For “why?”: code reduction (always a good thing) necessary … Read more
Base class constructors are automatically called for you if they have no argument. If you want to call a superclass constructor with an argument, you must use the subclass’s constructor initialization list. Unlike Java, C++ supports multiple inheritance (for better or worse), so the base class must be referred to by name, rather than “super()”. … Read more
You forgot the return types in your member function definitions: and so on.
The problem is that TeamLeader appears to be an inner class (hard to tell, your indentation is bad), and since it’s not static, you can’t instantiate it by itself. You either need to make TeamLeader its own class, or make it a static class and instantiate it as Employee.TeamLeader (or whatever the parent class is, your indentation is really not helpful here).
You’ve not included <string> header file in stock.h header file, even though you’re using std::string in it. Maybe that is causing this error message (if that is the case, then I would say its really a bad message). Another problem is that in Stock class definition, you’ve written this: which is wrong. Remove Stock:: from it, and make it like this: Stock:: is required when defining … Read more
If a constructor does not explicitly invoke a superclass constructor, the Java compiler automatically inserts a call to the no-argument constructor of the superclass. If the super class does not have a no-argument constructor, you will get a compile-time error. Object does have such a constructor, so if Object is the only superclass, there is … Read more
It’s wrong to say that a compiler-generated default constructor takes no action. It is equivalent to a user-defined constructor with an empty body and an empty initializer list, but that doesn’t mean it takes no action. Here is what it does: It calls the base class’es default constructor. It initializes the vtable pointer, if the … Read more
Yes, an abstract class can have a constructor. Consider this: The superclass Product is abstract and has a constructor. The concrete class TimesTwo has a constructor that just hardcodes the value 2. The concrete class TimesWhat has a constructor that allows the caller to specify the value. Abstract constructors will frequently be used to enforce class constraints or invariants such as … Read more