OOP Class12

Interfaces Part2

There are many interfaces in the .net framework. Some that we have been working with are the [ICollection https://msdn.microsoft.com/en-us/library/system.collections.icollection(v=vs.110).aspx] [IList https://msdn.microsoft.com/en-us/library/system.collections.ilist(v=vs.110).aspx] and [IEnumerable https://msdn.microsoft.com/en-us/library/system.collections.ienumerable(v=vs.110).aspx]

These interfaces allow us to use methods in a List and Array.

Here is an example of sorting a list of ints or an int[]

int[] ints = new int[] { 5, 4, 2, 3, 1 };
            foreach (var number in ints)
            {
                Console.Write(string.Format("{0}\t", number));
            }
            Console.WriteLine();

            Array.Sort(ints);
            foreach (var number in ints)
            {
                Console.Write(string.Format("{0}\t", number));
            }
            Console.WriteLine();
            
            ints = ints.Reverse().ToArray();
            foreach (var number in ints)
            {
                Console.Write(string.Format("{0}\t", number));
            }
            Console.WriteLine();

                        //mess it up again
            ints = new int[] { 5, 4, 2, 3, 1 };

            ints = ints.OrderBy(i => i).ToArray();
            foreach (var number in ints)
            {
                Console.Write(string.Format("{0}\t", number));
            }
            Console.WriteLine();

            //mess it up again
            ints = new int[] { 5, 4, 2, 3, 1 };

            //last way slightly uses agregate function to Order array by int, turns array into list so we can call foreach
            ints.OrderBy(i => i).ToList().ForEach(ii=>Console.Write(string.Format("{0}\t", ii)));
            Console.WriteLine();

now with List

Now lets sort some dogs

class Dog : IComparable
    {
        public string Name;
        protected int age;

        public int Age { get { return age; } set { age = value; } }

        public int Weight;
        public string BarkSound;

        public Dog()
        {
            this.Name = "fido";
            this.BarkSound = "woof!";
            this.Weight = 1;
        }

        public string About()
        {
            return string.Format("Hello my name is {0}. I'm {1} years old. I weigh {2} lbs", this.Name, this.Age, this.Weight);
        }



        public int CompareTo(object obj)
        {
            if (obj is Dog)
            {
                if (this.Age > ((Dog)obj).Age) return 1;
            }
            return 0;
        }
}

and finally override some operators

public static int Compare(Dog left, Dog right)
        {
            if (object.ReferenceEquals(left, right))
            {
                return 0;
            }
            if (object.ReferenceEquals(left, null))
            {
                return -1;
            }
            return left.CompareTo(right);
        }

        public static bool operator <(Dog left, Dog right)
        {
            return (Compare(left, right) < 0);
        }
        public static bool operator >(Dog left, Dog right)
        {
            return (Compare(left, right) > 0);
        }

Strategy Pattern

Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it.

http://www.dofactory.com/Patterns/PatternStrategy.aspx

Create Characters class and weapons class that uses the strategy pattern

http://iam.colum.edu/oop/classsource/ConsoleApplicationCharacters.zip

browser http://iam.colum.edu/oop/browser/browser.aspx?f=/classsource/ConsoleApplicationCharacters/ConsoleApplicationCharacters/ConsoleApplicationCharacters

Weapons

Characters

public abstract class Character : IDamagable
    {
        protected IWeapon currentWeapon;
        protected int hp;
        public string Name;

        public Character()
        {
            this.Name = "Character";
            this.hp = 100;
            this.currentWeapon = new Hands();
        }
        
        public int HP
        {
            get
            {
                return this.hp;
            }
            set
            {
                this.hp = value;
            }
        }

        public IWeapon CurrentWeapon
        {
            get
            {
                return this.currentWeapon;
            }
            set
            {
                this.currentWeapon = value;
            }
        }

        public string About()
        {
            //TODO write about
            return string.Format("About Character");
        }

        public string Attack(Character otherCharacter)
        {
            return string.Format("{0} {1} with {2} at {3} -{4} HP",
                this.Name, currentWeapon.Verb, this.currentWeapon.Name,  
                otherCharacter.Name, this.currentWeapon.Use(otherCharacter));
        }

        public int TakeDamage(int damage)
        {
            this.hp -= damage;
            return damage;
        }
    }

Than a specific character

public class Troll : Character { public Troll() { this.Name = "Troll"; this.currentWeapon = new WarHammer(); } }

public class SpaceMarine : Character { public SpaceMarine() { this.Name = "Master Chief"; this.currentWeapon = new BFG(); } }

Notice the IWeapon becomes a specific interchangeable weapon.

Use Case

http://en.wikipedia.org/wiki/Use_case

Diagrams

http://en.wikipedia.org/wiki/Use_case_diagram

Windows Course App Use Case

Actors

particiant outside of the system

Activity

something an actor does

Version 1 breif use case

Actor Admin

Course
#Add a course to the system
#Delete a course to the system
Student
#Add a student to the system
#Delete a student to the system
#Student add a course
#Student remove a course

Home work

Toastable project in moodle

Make one of your classes sortable by implementing IComparable