FAQ: Interfaces - Build an Interface

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This community-built FAQ covers the “Build an Interface” exercise from the lesson “Interfaces”.

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FAQs on the exercise Build an Interface

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2

Could someone please explain how interfaces work with an analogy and what they are used for.
Thank you.

4 Likes
3

To me, interface is like instructions that tell a class what it should do/have.

When you’re developing a game which that needs classes like warrior, mage, gunslinger, or maybe more.

At some point, you might forget to add a property let’s say “weapon” to some of the classes. Here’s interface comes to the rescue.

It tells you what properties you forgot to add to classes that implement to the interface.

interface IClass
{
    string Title { get; private set; }
    string Weapon { get; private set; }
    bool WeaponIsOneHanded { get; private set; }
}

Then we want our classes to promise to the interface and implement its properties.

Class Warrior : IClass
{
    // constructors
    public Warrior(string title, string weapon, bool weaponIsOneHanded)
    {
        Title = title;
        Weapon = weapon;
        WeaponIsOneHanded = weaponIsOneHanded;
    }

    // properties
    public string Title { get; private set; }
    public string Weapon { get; private set; }
    public bool WeaponIsOneHanded { get; private set; }
}

If you forget to add some properties such as Weapon then the interface will tell you to implement it, because it doesn’t make sense when warriors have no swords.

Then we call it in the Main method.

class Program
{
    public static void Main(string[] args)
    {
        Warrior w = new Warrior("Some Name", "Greatsword", false);
    }
}
10 Likes