What is the use of this ?

[MaGx]

Hello , I am learning c# currently .. I was looking for some sources on internet to learn and so I found this code , I understand everything but this part :

public Calculator(double l, double w) : base(l, w) { }

/// base.Display();

What is base ? Just explain me how and why is base created .. I really don't understand !

Here's my code :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace InheritanceApplication
{
    class Rectangle
    {
        protected double length;
        protected double width;

        public Rectangle(double l, double w) 
        {
            length = l;
            width = w;
        }

        public double GetArea()
        {
            return width * length;
        }
        public void Display()
        {
            Console.WriteLine("Length: {0}", length);
            Console.WriteLine("Width: {0}", width);
            Console.WriteLine("Area: {0}", GetArea());
        }
    }

    class Calculator : Rectangle
    {
    
        public Calculator(double l, double w) : base(l, w) { }
        public double GetCost()
        {
            double cost;
            cost = GetArea() *50;
            return cost;
        }
        public void Display()
        {
            base.Display();
            Console.WriteLine("Cost: {0}", GetCost());
        }

    }

    class Execute
    { 
    
        static void Main()
        {
            Calculator kenny = new Calculator(2.5, 3.5);
            kenny.Display();
        }
    }
}

Thank you vm for your time

[Biesi]

Your Calculator class inherits from the Rectangle class. The base keyword is used to access the underlying Rectangle class members. While the this keyword represents the current instance of your Calculator class.

Inheritance (C# Programming Guide)