Introduction to C# and Databases - Homework

1. Introduction to C# and Databases - Homework Doncho Minkov Technical Trainer http://www.minkov.it Telerik School Academy schoolacademy.telerik.com

2. C# Overview • Write a program that, for a given two integer numbers N and X, calculates the sumS = 1 + 1!/X + 2!/X2 + … + N!/XN • Write a program that reads a number N and calculates the sum of the first N members of the sequence of Fibonacci: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, … Each member of the Fibonacci sequence (except the first two) is a sum of the previous two members. • Write a program that calculates the greatest common divisor (GCD) of given two numbers. Use the Euclidean algorithm (find it in Internet).

3. C# Overview (2) • Write a program that fills a matrix of size (N, N) as shown in the examples (for N=4): a) b) *c) *d)

4. C# Overview (3) • * Write a program that converts a number in the range [0...999] to a text corresponding to its English pronunciation. Examples: 0  "Zero" 273  "Two hundred seventy three" 400  "Four hundred" 501  "Five hundred and one" 711  "Severn hundred and eleven"

5. C# Overview (4) • Write a program that reads a list of words, separated by spaces and prints the list in an alphabetical order. • Write a program to check if in a given expression the brackets are put correctly. Example of correct expression: ((a+b)/5-d). Example of incorrect expression: )(a+b)). • Write a program that generates and prints to the console 10 random values in the range [100,200]. • Write a program that prints to the console which day of the week is today. Use System.DateTime.

6. C# Overview (5) • Write a program that parses an URL address given in the format: and extracts from it the [protocol], [server]and[resource] elements. For example from the URL http://www.devbg.org/forum/index.phpthe following information should be extracted: [protocol] = "http" [server] = "www.devbg.org" [resource] = "/forum/index.php" [protocol]://[server]/[resource]

7. C# OOP • We are given a library of books. Define classes for the library and the books. The library should have name and a list of books. The books have title, author, publisher, year of publishing and ISBN. Keep the books in List<Book> (first find how to use the class System.Collections.Generic.List<T>). • Implement methods for adding, searching by title and author, displaying and deleting books. • Write a test class that creates a library, adds few books to it and displays them. Find all books by Nakov, delete them and print again the library.

8. LINQ • Create a class student with properties FirstName, LastName, FN, Tel, Email, Marks(aList<int>), GroupNumber. Create a List<Student> with sample students. Select only the students that are from group number 2. Use LINQ query. Order the students by FirstName. • Implement the previous using the same query expressed with extension methods. • Extract all students that have email in abv.bg. Use string methods and LINQ. • Extract all students with phones in Sofia. Use LINQ and regular expressions.

9. LINQ (2) • Select all students that have at least one mark Excellent (6) into a new anonymous class that has properties – FullName and Marks. Use LINQ. • Write down a similar program that extracts the students with exactly two marks "2". Use extension methods. • Extract all Marksof the students that enrolled in 2006. (The students from 2006 have 06 as their 5-th and 6-th digit in the FN). • Create a program that extracts all students grouped by GroupName and then prints them to the console. Use LINQ.

10. Entity Framework • Using the Visual Studio Entity Framework designer create a ObjectContext for the Northwind database • Create a DAO class with static methods which provide functionality for inserting, modifying and deleting customers. Write a testing class. • Write a method that finds all customers who have orders made in 1997 and shipped to Canada. • Implement previous by using native SQL query and executing it through the ObjectContext. • Write a method that finds all the sales by specified region and period (start / end dates).

11. Entity Framework (2) • Create a database called NorthwindTwin with the same structure as Northwind using the features from ObjectContext. Find for the API for schema generation in MSDN or in Google. • Try to open two different data contexts and perform concurrent changes on the same records. What will happen at SaveChanges()? How to deal with it? • By inheriting the Employee entity class create a class which allows employees to access their corresponding territories as property of type EntitySet<T>.

12. Entity Framework (3) • Create a method that places a new order in the Northwind database. The order should contain several order items. Use transaction to ensure the data consistency. • Create a stored procedures in the Northwind database for finding the total incomes for given supplier name and period (start date, end date). Implement a C# method that calls the stored procedure and returns the retuned record set.