# Exercise: Dependency Injection

Exercise: Dependency Injection: Exercise: Dependency Injection.

Updated: November 3, 2026

1. [Exercise: Dependency Injection](https://www.ask-codey.com/lessons/exercise-dependency-injection) (Journeyman): Write a cinema box office that is given its clock and price list, sells each seat once with a HashSet, keeps a waiting list in a Queue, and undoes sales with a Stack.

Source: https://www.ask-codey.com/courses/csharp-full-stack-bootcamp/topics/exercise-dependency-injection