Question

4. Create a class library (.dll) in a particular namespace (using csc or VS2017) to define one or more classes, each contains fields, methods, constructors, and/or properties, including r/w properties, auto-implemented and/or expression-bodied properties.

Answer 1

Below is the class library code.

using System;

namespace MyClassLibrary
{
    public class MyLibraryClass
    {
        //Fields
        private string name;
        private int age;

        private int _rollNumber;

        // Auto-implemented properties
        public string Division { get; set; }

        //Read Write Property. It has both get and set accessor hence considered as read/write properties.
        public int RollNumber
        {
            get
            {
                return _rollNumber;
            }
            set
            {
                _rollNumber = value;
            }
        }

        //Read only property
        public string TestMessage
        {
            get
            {
                return "Hello!";
            }
        }

        //Default constructor
        public MyLibraryClass()
        {

        }

        //Parameteric constructor
        public MyLibraryClass(int rollNumber, string division)
        {
            this.RollNumber = rollNumber;
            this.Division = division;
        }

        public MyLibraryClass(string stateName, string country)
        {
            this.StateName = stateName;
            this.CountryName = country;
        }

        //Method with zero parameter.
        public int getSquareOfTwo()
        {
            int square = 2 * 2;
            return square;
        }

        //Method with two parameters
        public int getMultiplication(int a, int b)
        {
            int multiplication = a * b;
            return multiplication;
        }

        //expression-body properties
        public string StateName { get; set; }
        public string CountryName { get; set; }

        public string CountryState => $"{CountryName} {StateName}";
    }
}

Follow below step to create class library.

Open visual studio
Create new project
Under Visual C#, Create class library.
Give Name as per your choice