Please use C#   using System; namespace UsernameProcessor.Question; public sealed class UsernameProcessorService { /// /// Requirements: /// - A valid username shall be at least 4 characters. /// - A valid username shall contain only letters, numbers and an optional underscore. /// - A valid username shall start with a letter, and shall not end with an underscore. /// ///The username to be validated ///Whether or not the username is valid per the above requirements. publicstaticboolIsValidUsername(stringusername) { thrownewNotImplementedException("TODO: please validate our usernames!!!"); } /// /// Feel free to use the below main function to test and develop accordingly! /// publicstaticvoidMain(string[]args) { Console.WriteLine(IsValidUsername("Valid_Username")); Console.WriteLine(IsValidUsername("Invalid Username")); } }

C++ Language   Please fill in the blanks for the following statements: The file extension for the file that contains the class definition is ______________.

Portfolio Instructions: You are working for a financial advisor who creates portfolios of financial securities for his clients. A portfolio is a conglomeration of various financial assets, such as stocks and bonds, that together create a balanced collection of investments. When the financial advisor makes a purchase of securities on behalf of a client, a single transaction can include multiple shares of stock or multiple bonds. It is your job to create an object-oriented application that will allow the financial advisor to maintain the portfolios for his/her clients. You will need to create several classes to maintain this information: Security, Stock, Bond, Portfolio, and Date. The characteristics of stocks and bonds in a portfolio are shown below: Stocks:                                                                        Bonds: Purchase date (Date)                                                   Purchase date (Date) Purchase price (double)…

Problem Statement: Develop an Inventory Management System (IMS) for a small retail business that allows the user to manage their product inventory. The system should enable the user to add, edit, update, and delete product information stored in a .csv file. The IMS should be console-based with a menu-driven interface. Requirements: 1. Classes and Objects: - Create a `Product` class with attributes such as `productID`, `productName`, `price`, `quantity`. - Implement a `InventoryManager` class that will handle operations like adding, editing, updating, and deleting products. - Use a `Main` class with the `main` method to run the program and display the menu. 2. File Operations: - Store product information in a .csv file named `inventory.csv`. - Implement methods in `InventoryManager` for reading and writing to the .csv file. 3. Menu-Driven Interface: - Implement a menu in the `Main` class that allows the user to select operations like Add, Edit, Update, Delete, and View Inventory. - Use…

A) Class: A class in C++ is the building block that leads to object-oriented programming. true or false B) Conversion operator: We can also write conversion operators that can be used to convert one type to another type. true or false

A(n) is a unique form of class member that enables an object to store and retrieve data.

Using C# language: Programming PLO-2 Measured: Design, implement, and evaluate computer solutions utilizing structured and object-oriented programming methodologies.   Design a class named Contractor. The class should keep the following information:   Contractor name Contractor number Contractor start date   Write one or more constructors and the appropriate accessor and mutator functions for the class.

structions: Write the following programs in C# using concepts learnt in this chapter and abmit the .cs file with the screenshot of your output for each question in the Lab Assignment 2 Submission page. 1. FRENCH TRANSLATOR Look at the following list of French words and their meanings: In French: gauche milieu droite middle In English: right left Create an application that translates the French words to English. The form should have three buttons, one for each French word. When the user clicks a button, the application should display the English translation in a Label control.