Question

C# for beginners (Methods and Properties, Data types)

WorkStation:- Visual Studio 2019

Create a class called Invoice that a hardware store might use to represent an invoice for an item sold at the store. An Invoice should include four pieces of information as instance variables – a part number (type int), a part description (type string), a quantity of the item being purchased (type int) and a price per item (type decimal). Your class should have a constructor that initializes the four instance variables. Provide a property with a get and set for each instance variable. In addition, provide a method named GetInvoiceAmount that calculates the invoice amount (i.e. multiplies the quantity by price per item), then returns the amount as a decimal value. If the quantity is negative, it should be left unchanged. Similarly, if the price per item is negative, it should be left unchanged.

Create the class diagram for class Invoice.

Write a test console application named InvoiceTest that demonstrates class Invoice’s capabilities. Allow user to enter invoice information. Use properties and methods of class Invoice to process the information and output the results

Answer 1

Visual C# Console Application

Code for Invoice.cs:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace InvoiceProject //Change this namespace if you save project with different name.

{

public class Invoice

{

//instance variables

private string partNumber;

private string partDescription;

private int quantity;

private decimal pricePerItem;

//Constructor

public Invoice(string part, string description, int quantity, decimal price)

{

PartNumber = part;

Description = description;

Quantity = quantity;

Price = price;

}//end constructor

// PartNumber Property

public string PartNumber

{

get

{

return partNumber;

}

set

{

partNumber = value;

}

}

// Description Property

public string Description

{

get

{

return partDescription;

}

set

{

partDescription = value;

}

}

//Method GetInvoiceAmount() returns the total invoice

public decimal GetInvoiceAmount()

{

return Price * Quantity;

}

//Begin Instance Variable Property Assignment

public int Quantity

{

get

{

return quantity;

} //end get

set

{

if (value >= 0)

quantity = value;

} //end set

}//end property Quantity

public decimal Price

{

get

{

return pricePerItem;

} //end get

set

{

if (value >= 0)

pricePerItem = value;

} //end set

}//end property Price

}//end Invoice class

}

Rename the Program.cs file to InvoiceTest.cs in the solution explorer.
Code for InvoiceTest.cs:
using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace InvoiceProject

{

class InvoiceTest

{

static void Main(string[] args)

{

Invoice invoice1 = new Invoice("AV676","Intro to C#", 50, 250);

Invoice invoice2 = new Invoice("IS542", "Starting out with VB", 5, 50);

Console.WriteLine("*********INVOICE 1*********");

Console.WriteLine("Part number : {0}", invoice1.PartNumber);

Console.WriteLine("Description : {0}", invoice1.Description);

Console.WriteLine("Price : {0}", invoice1.Price);

Console.WriteLine("Quantity : {0}", invoice1.Quantity);

Console.WriteLine("Total : {0}", invoice1.GetInvoiceAmount());

Console.WriteLine("*********INVOICE 2*********");

Console.WriteLine("Part number : {0}", invoice2.PartNumber);

Console.WriteLine("Description : {0}", invoice2.Description);

Console.WriteLine("Price : {0}", invoice2.Price);

Console.WriteLine("Quantity : {0}", invoice2.Quantity);

Console.WriteLine("Total : {0}", invoice2.GetInvoiceAmount());

Console.ReadKey();

}

}

}

Note: Add a Class File to the Project (Right-Click on the solution, Add->Class) and Save it as Invoice.cs