How can polymorphism be implemented in C#?

In C#, polymorphism is typically achieved through inheritance and interfaces. The specific methods are as follows:

1. Inheritance: By creating a parent class and multiple child classes, the child classes inherit the characteristics of the parent class and can override the parent class’s methods to achieve polymorphism. For example:

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

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

class Cat : Animal
{
    public override void MakeSound()
    {
        Console.WriteLine("Cat meows");
    }
}

Animal myDog = new Dog();
Animal myCat = new Cat();

myDog.MakeSound(); // Output: Dog barks
myCat.MakeSound(); // Output: Cat meows

1. Interface: By defining an interface and then having multiple classes implement this interface, it allows for polymorphism of interface methods. For example:

interface IShape
{
    double GetArea();
}

class Circle : IShape
{
    public double Radius { get; set; }

    public double GetArea()
    {
        return Math.PI * Radius * Radius;
    }
}

class Rectangle : IShape
{
    public double Width { get; set; }
    public double Height { get; set; }

    public double GetArea()
    {
        return Width * Height;
    }
}

IShape myCircle = new Circle() { Radius = 5 };
IShape myRectangle = new Rectangle() { Width = 5, Height = 10 };

Console.WriteLine(myCircle.GetArea()); // Output: 78.54
Console.WriteLine(myRectangle.GetArea()); // Output: 50

By using these two methods, it is possible for objects of different classes to call the same method, achieving polymorphism.