Inheritance

[Guest]

I am attempting to learn OOP. The book uses C++ examples. I am trying to
convert the code to C#. C# doesn't like the statement Person:isplay(); in
the Student class. How do I need to modify this to work in C#? Thanks for
your help.

using System;

namespace LevelInheritance
{
public class Person
{
protected int m_ID;
protected string m_First;
protected string m_Last;

public Person()
{

m_ID = 0;
m_First = "\0";
m_Last = "\0";
}

public virtual void Display()
{
Console.WriteLine("ID: " + m_ID +
"\rFirst: " + m_First +
"\rLast: " + m_Last);
}

public void Write(int ID, string First, string Last)
{
m_ID = ID;
m_First = First;
m_Last = Last;
}
}

class Student: Person
{
protected int m_Graduation;

public override void Display()
{
Person:isplay();
Console.WriteLine("Graduation: " + m_Graduation);
}


public void Write(int ID, string First, string Last, int Graduation)
{
Write(ID, First, Last);
m_Graduation = Graduation;
}

public Student()
{
m_Graduation = 0;
}
}

 

[Patrice]

Use . Instead of ::

 

[Guest]

I receive an error with the dot also. The error is below

An object reference is required for the nonstatic field, method, or property
'LevelInheritance.Person.Display()'

 

[carlovella]

You have to understand what is an instance and what is a static method.
If person or display is an instance property then you have to create an
instance of the object (ie, new ...)

 

[Mattias Sjögren]

C# doesn't like the statement Person:isplay(); in
the Student class. How do I need to modify this to work in C#?

You use the base keyword to call the base class' implementation of a
virtual method from an override.

base.Display();

Since C#, unlike C++, only supports a single base class, there's no
need to explicitly name it.


Mattias

 

[alantolan]

From the context it looks like it was trying to call the Display()

method of the Person class , followed by specific class code - this
makes sense as :: is used as a scope qualiifer in C++

For this, you would use

base.Display();

instead of

Person:isplay();


hth,

Alan.

 

[Guest]

Thank you very much. The base.Display(); worked great!