Learn Object-Oriented Programming in C#/

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Declaration and Implementation

Declaration and Implementation

In this lesson, you will learn about the declaration and implementation details of a class.

We'll cover the following...

Declaration

In C#, we declare classes in the following way:

C#
class ClassName // Class name
{ 
    /* All member variables
    and methods */
}

The keyword class tells the compiler that we are creating our custom class. All the members of the class will be defined within the class scope, i.e., inside the curly brackets, {...}.

Creating a Class Object

The name of the class, ClassName, will be used to create an instance/object of the class in our Main() method. We can create an object of a class by using the new keyword:

C#
class ClassName  //Class name
{
  ...
}
class Program //Class having the Main() method
{ 
    public static void Main(string[] args) //Main method
    { 
        ClassName objectOneName = new ClassName(); //ClassName first object 
        var objectTwoName = new ClassName(); //ClassName second object
    }
}

In the above snippet, we can see that there are two ways we can create an object of a class. We can use the name of the class on both sides of the assignment operator or we can use the var keyword on the left side and the name of the class on the other. When using var, the compiler automatically infers the type of the object being created from the right side of the assignment operator.

đź“ť Whenever the compiler comes across the keyword new, it realizes that an object is being created and allocates a separate memory location for the object being created.

Implementation of the VendingMachine Class

Let’s implement the VendingMachine class illustrated below:

C#
class VendingMachine //Class name
{   
    //Class fields
    int count;
    int capacity;
    int moneyCollected;
    string manufacturer;
    //Class Methods
    void Display()
    {
        //Method definition goes here
    }
    void DispenseProducts()
    {
        //Method definition goes here
    }
    void Refill()
    {
        //Method definition goes here
    }
}

Now that we have learned how to declare and implement a class in C#, let’s briefly discuss the naming conventions we should follow when working with classes.

Naming Conventions

  • The name of a class should preferably be a noun so that it represents the actual purpose of creating that class, e.g., VendingMachine, Calculator, etc.

  • While naming a class, we should use the PascalCase.

  • While naming the methods in a class we should use the PascalCase.

The naming conventions of fields will be discussed in the upcoming lesson.

We’ve seen the structure of a class and the basic skeleton of the VendingMachine class. In the next lesson, we will build upon this by creating an object of the vending machine class and accessing the class members through it.