link: Object Oriented Programming , Relations Between Objects

Dependency relationships

Content

Dependency is the most basic and the weakest type of relations between classes. In object-oriented programming (OOP), a dependency exists whenever one class uses another. This can be through direct instantiation, method calls, or through passing instances as parameters. Dependencies make one class reliant on another, often leading to a higher risk of bugs when changes are made:

Example

Here’s a practical C# example illustrating a basic dependency relationship:

csharp

using System;
 
public class Car
{
   public void Start() => Console.WriteLine("Car started");
   public void Stop() => Console.WriteLine("Car stopped");
}
 
public class Driver
{
   public void Drive(Car car)
   {
       car.Start();
       Console.WriteLine("Car is being driven by the driver");
       car.Stop();
   }
}
 
class Program
{
   static void Main()
   {
       Car myCar = new Car();      // Creating a Car object
       Driver john = new Driver(); // Creating a Driver object
 
       john.Drive(myCar);  // Demonstrating dependency
   }
}
 

In this code:

• The Driver class has a dependency on the Car class because it uses the Car object to perform its functions. The method Drive directly interacts with Car, implying that any change in Car’s interface would require changes in Driver.

Example

This C# code snippet demonstrates a clear dependency where Driver relies on Car. Such dependencies are vital to identify as they dictate the robustness and flexibility of your code structure.

References

https://refactoring.guru/design-patterns