C# : Interview questions (11-15)

  Questions :

• What is inheritance in C#?
• Explain the concept of method overloading.
• What is method overriding?
• What is an abstract class in C#?
• What is an interface?

C# : Interview questions (6-10)

Answers :

Inheritance in C#:

Inheritance is a fundamental feature of object-oriented programming (OOP) that allows a class (called a subclass or derived class) to inherit properties and behaviors from another class (called a superclass or base class). In C#, inheritance is implemented using the : symbol followed by the name of the base class.

class Animal // Base class
{
    public void Eat() 
    {
        Console.WriteLine("Animal is eating...");
    }
}

class Dog : Animal // Derived class inheriting from Animal
{
    public void Bark() 
    {
        Console.WriteLine("Dog is barking...");
    }
}

In this example, the Dog class inherits the Eat method from the Animal class, allowing instances of Dog to both eat and bark.

Method Overloading:

Method overloading is a feature in C# that enables a class to have multiple methods with the same name but different parameter lists within the same scope. The parameters may differ in number, type, or both. This allows for flexibility and code organization.

class Calculator
{
    public int Add(int a, int b)
    {
        return a + b;
    }

    public double Add(double a, double b)
    {
        return a + b;
    }
}

Here, the Add method is overloaded with two different parameter types (int and double), allowing the calculator class to handle both integer and floating-point addition.

Method Overriding:

Method overriding is a concept in inheritance that allows a derived class to provide a specific implementation for a method that is already defined in its base class. To override a method, the method in the derived class must have the same name, return type, and parameters as the method in the base class, and it must be marked with the override keyword.

class Animal 
{
    public virtual void MakeSound() 
    {
        Console.WriteLine("Animal is making a sound...");
    }
}

class Dog : Animal 
{
    public override void MakeSound() 
    {
        Console.WriteLine("Dog is barking...");
    }
}

In this example, the MakeSound method is overridden in the Dog class to provide a specific implementation for the sound a dog makes.

Abstract Class in C#:

An abstract class in C# is a class that cannot be instantiated directly and may contain abstract methods, which are methods without a body. Abstract classes are meant to serve as base classes for other classes and define a common interface that derived classes must implement.

abstract class Shape 
{
    public abstract void Draw();
}

class Circle : Shape 
{
    public override void Draw() 
    {
        Console.WriteLine("Drawing a circle...");
    }
}

In this example, Shape is an abstract class with an abstract method Draw. The Circle class inherits from Shape and provides an implementation for the Draw method.

Interface:

An interface in C# is a reference type that defines a contract for classes to implement. It contains method signatures, properties, events, and indexers without any implementation. Classes that implement an interface must provide concrete implementations for all members defined by the interface.

interface IShape 
{
    void Draw();
}

class Circle : IShape 
{
    public void Draw() 
    {
        Console.WriteLine("Drawing a circle...");
    }
}

In this example, IShape is an interface with a single method Draw. The Circle class implements the IShape interface by providing an implementation for the Draw method.

These concepts are foundational to understanding and building object-oriented applications in C#.

C# : Interview questions (16-20)