[Answer] Problem #3 EXAM dotnetstarter.blogspot.com

Copy and paste this code to answer the question. for the question, just click the title.

using System;
using System.Collections.Generic;
using System.Text;

namespace Exam01
{
   class Program
   {
       static void Main(string[] args)
       {
           Book book1 = new Book();
           book1.Type = BookType.Science;
           book1.Pages = 150;
           book1.Title = "Practical Science";
           book1.Author = "Professor X1";    // Displays an error since the author name has a digit        
           Console.WriteLine(book1.Author);  // Displays 'Unknown' since the author field is blank
           book1.Author = "Professor X";
           Console.WriteLine(book1);  // Display's 'Type: Science, Title: Practical Science, Author: Professor X, Pages: 150'

           Book book2 = new Book(BookType.History, "World History", "Magellan");

           book2.Borrow();  // Sets the book status to borrowed
           Console.WriteLine(book2.IsBorrowed);  // Displays true
           book2.Borrow();  // Displays an error since book is already borrowed

           book2.Return();  // Sets the book status to available
           Console.WriteLine(book2.IsBorrowed);  // Displays false
           book2.Return();  // Displays an error since book is already returned

           Console.ReadLine();
       }
   }
   public enum BookType
   {
       Undefined,
       Fiction,
       NonFiction,
       History,
       Science
   }

   public enum StatusType
   {
       Undefined,
       Available,
       Borrowed
   }

   public class Book
   {
       #region "fields"
       private int _pages;
       private string _title;
       private string _author;
       private BookType _bookType;
       private StatusType _statusType;
       #endregion
       #region "Constructors"
       public Book(BookType bookType, string title, string author, int pages)
       {
           _pages = pages;
           _title = title;
           _author = author;
           _bookType = bookType;
           _statusType = StatusType.Available;
       }
       public Book(BookType bookType, string title, string author)
       { }
       public Book(string title,string author)
       { }
       public Book()
       { }
       #endregion
       #region "Propertys"
       public string Title
       {
           get{return _title;}
           set{_title = value;}
       }
       public string Author
       {
           get
           {
               if (_author == "")
               {
                   return "'Unknown' since the author field is blank";
               }
               else
                   return _author;
           }
           set
           {
               if (value.Contains("1") || value.Contains("2") || value.Contains("3") || value.Contains("4") || value.Contains("5") || value.Contains("6") || value.Contains("7") || value.Contains("8") || value.Contains("9") || value.Contains("0"))
               {
                   Console.WriteLine("error since the author name has a digit");
                   _author = "";
               }
               else
                   _author = value;
           }
       }
       public int Pages
       {
           get { return _pages; }
           set { _pages = value; }
       }
       public BookType Type
       {
           get { return _bookType; }
           set { _bookType = value; }
       }
       public bool IsBorrowed
       {
           get
           {
               if (_statusType == StatusType.Borrowed)
                   return true;
               else
                   return false;
           }
       }

       #endregion

       #region "methods"
       public void Borrow()
       {
           if (IsBorrowed == true)
               Console.WriteLine("error since book is already borrowed");
           else
               _statusType = StatusType.Borrowed;
       }
       public void Return()
       {
           if(_statusType==StatusType.Available)
               Console.WriteLine("error since book is already returned");
           else
               _statusType = StatusType.Available;
       }
       #endregion
       public override string ToString()
       {
           return "Type: "+_bookType+", Title: "+_title+", Author: "+_author+", Pages: "+_pages; 
          
       }
   }
}