Why can't I use inherited objects in my inherited class?

user_13619428 0
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    class Vehicle  // base class (parent) 
    {
      public string brand = "Ford";  // Vehicle field
      public void honk()             // Vehicle method 
      {                    
        Console.WriteLine("Tuut, tuut!");
      }
    }
    
    class Car : Vehicle  // derived class (child)
    {
      public string modelName = "Mustang";  // Car field
      brand = "WHY İS NOT ??? "; // Error.

  public void honk(); // Error.
}

Can't I do that? Does the class we inherit have its functions, methods, and variables? Did I learn something wrong?

Note; It works within the main function.

I've been dealing with this for a long time. : / (3+ hours)

inheritance c#
1 Answers

You can't just write to a field (defined in a base class) from the derived class like:

brand = "WHY İS NOT ??? "; // Error.

...because you aren't definining a new field, rather you are attempting to change brand defined in the the base class Vehicle. Unfortunately the way it is written, the compiler thinks it's an orphaned assignment. It should exist in a in a method or constructor.

Try placing it in a constructor:

class Car : Vehicle  // derived class (child)
{
      public string modelName = "Mustang";  // Car field

      public Car()
      {
          brand = "Acme"; 
      }

      public void honk() {}
}

Honk

public void honk(); // Error.

The problem here is that your method has no body. Whilst you can do that in an interface you can't in a non-abstract method belonging to a class.

Give it a minimal one like so:

public override void honk() { }

...or:

public override void honk() 
{
   // same thing but formatted differently
}

Notice there is a new override. If you want a new implementation of honk in a derived class it's best to make the method virtual.

i.e.

class Vehicle  // base class (parent) 
    {
      // ...

      public virtual void honk()           
      {                    
        Console.WriteLine("Tuut, tuut!");
      }

      // ...
    }

Alternatively you can use new instead of override but there are gotchas.

user_5859680
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