Skip to content

Latest commit

 

History

History
165 lines (94 loc) · 3.12 KB

FinalExam.md

File metadata and controls

165 lines (94 loc) · 3.12 KB

Final Exam 2019/12/17 (4:15pm-6:15pm)

The final exam will be held in class on Tuesday 2019/12/17. You will not be allowed to use any reference while taking the exam. Bring a pen.

Ternary Statements (2 points)

int i = 3;
i += i < 5 ? 2 : 3;
// What is the value of `i`? _______
i += i < 5 ? 4 : 6;
// What is the value of `i`? _______

Thread Safety (10 points)

Consider this code that your co-worker wrote:

class Program
{
	static void Main(string[] args)
	{
		Parallel.For(0, 10000, i => new House(i % 3, i % 4));
		Console.WriteLine(House.HousesBuilt);
	}
}

public class House
{
	int Beds;
	int Baths;
	static int HousesBuilt;

	public House(int beds, int baths)
	{
		Beds = beds;
		Baths = baths;
		// Some time-consuming operation goes here (I don't know, maybe a database call).
		HousesBuilt = HousesBuilt + 1;
	}
}

Building a House involves some time-consuming operation and your co-worker saves time by making many of them in parallel. But, after making 10,000 Houses, the console output shows that it only made 9,665 Houses. Show how you would fix the House class to make it thread-safe (outputting 10,000) without removing the multi-threading.

Efficient Algorithms (10 points)

Your co-worker wrote this code and there are a lot of Dogs and Cats. It runs really slow. Re-write it (fix this so it is better than O(n^2)).

public Dog GetFirstDogWithACatsName(Dog[] dogs, Cat[] cats)
{
	foreach (Cat cat in cats)
	{
		foreach (Dog dog in dogs)
		{
			if (dog.name == cat.name)
			{
				return dog;
			}
		}
	}
}

Vocab match (1 point per match)

Write the number of the definition next to the matching word. Not all words and definitions have a match, if they don't match, don't match them.

  1. A declarative markup language which simplifies the creation of a UI for a .NET desktop app.
  2. A generic data structure which stores key-value pairs and has efficient O(1) lookup operations.
  3. A type of function which calls itself.
  4. A cross-platform, open-source development platform supported by Microsoft.
  5. A keyword which prevents two threads from executing in a code block at the same time.
  6. A keyword which modifies things so they belong to the type itself, not to an instance of the type.
  • xaml
  • .Net Framework
  • yield
  • winforms
  • .Net Core
  • HashSet
  • readonly
  • break
  • .Net Standard
  • static
  • Dictionary
  • lock
  • Contains()

Write a Function (10 points)

Write a function which takes a string and returns how many "descending" letters are in the string (lowercase g, j, q, p, and y). It could be used like this int descending = CountDescendingLetters("Ping pong? Yes please!"); // Should be 4

Convince Me

Convince me you know what these words mean. You could give a reason you would use one, explain what they do, or show examples.

  • Solution File (3 points)
  • Project Reference (3 points)
  • NuGet Package (3 points)