C#•2y ago

❔ Is this the right way to implement an Interface

    interface IObstacles
    {
        void Draw(Graphics g);
    }

    class Redbox : IObstacles
    {
        Pen Pen = new Pen(Color.Red);

        Random Random = new Random();
        Position Position;

        float width;
        float height;

        public Redbox(float x, float y)
        {
            Position = new Position(x, y);

            width = Random.Next(30, 100);
            height = Random.Next(30, 100);
        }


        public void Draw(Graphics g)
        {
            g.DrawRectangle(Pen, Position.X , Position.Y, width, height);
        }
    }

    class Bluebox: IObstacles
    {
        Pen Pen = new Pen(Color.Blue);

        Random Random = new Random();
        Position Position;

        float width;
        float height;

        public Bluebox(float x, float y)
        {
            Position = new Position(x, y);

            width = Random.Next(30, 100);
            height = Random.Next(30, 100);
        }

        public void Draw(Graphics g)
        {
            g.DrawRectangle(Pen, Position.X, Position.Y, width, height);
        }

    }

    class VerticaLine : IObstacles
    {
        Pen Pen = new Pen(Color.Yellow);

        Position Position;

        float Radius;

        public VerticaLine(float x, float y, float radius)
        {
            Position = new Position(x, y);
            Radius = radius;
        }

        public void Draw(Graphics g)
        {
            g.DrawLine(Pen, Position.X, Position.Y, Position.X, Radius);
        }
    }

    class HorizonaLine : IObstacles 
    {
        Pen Pen = new Pen(Color.Green);

        Position Position;

        float Radius;

        public HorizonaLine(float x, float y, float radius)
        {
            Position = new Position(x, y);
            Radius = radius;
        }

        public void Draw(Graphics g)
        {
            g.DrawLine(Pen, Position.X, Position.Y, Radius, Position.Y);
        }
    }

    interface IObstacles
    {
        void Draw(Graphics g);
    }

    class Redbox : IObstacles
    {
        Pen Pen = new Pen(Color.Red);

        Random Random = new Random();
        Position Position;

        float width;
        float height;

        public Redbox(float x, float y)
        {
            Position = new Position(x, y);

            width = Random.Next(30, 100);
            height = Random.Next(30, 100);
        }


        public void Draw(Graphics g)
        {
            g.DrawRectangle(Pen, Position.X , Position.Y, width, height);
        }
    }

    class Bluebox: IObstacles
    {
        Pen Pen = new Pen(Color.Blue);

        Random Random = new Random();
        Position Position;

        float width;
        float height;

        public Bluebox(float x, float y)
        {
            Position = new Position(x, y);

            width = Random.Next(30, 100);
            height = Random.Next(30, 100);
        }

        public void Draw(Graphics g)
        {
            g.DrawRectangle(Pen, Position.X, Position.Y, width, height);
        }

    }

    class VerticaLine : IObstacles
    {
        Pen Pen = new Pen(Color.Yellow);

        Position Position;

        float Radius;

        public VerticaLine(float x, float y, float radius)
        {
            Position = new Position(x, y);
            Radius = radius;
        }

        public void Draw(Graphics g)
        {
            g.DrawLine(Pen, Position.X, Position.Y, Position.X, Radius);
        }
    }

    class HorizonaLine : IObstacles 
    {
        Pen Pen = new Pen(Color.Green);

        Position Position;

        float Radius;

        public HorizonaLine(float x, float y, float radius)
        {
            Position = new Position(x, y);
            Radius = radius;
        }

        public void Draw(Graphics g)
        {
            g.DrawLine(Pen, Position.X, Position.Y, Radius, Position.Y);
        }
    }

26 Replies

ero•2y ago

The code style definitely isn't perfect, but this is certainly a way to implement interfaces. It's perfectly valid and a fine idea, it's just more important how you use the interface in your code

XellezOP•2y ago

I have a class that draws multiple shapes

public class Engine
    {
        MainForm Form = new MainForm();
        Timer Timer = new Timer();
        List<Ball> Balls = new List<Ball>();
        List<Redbox> RBox = new List<Redbox>();
        Random Random = new Random();

        public void Run()
        {
            Form.Paint += Draw;
            Timer.Tick += TimerEventHandler;
            Timer.Interval = 1000/25;
            Timer.Start();

            Application.Run(Form);
        }

        private void Form_Paint(object sender, PaintEventArgs e)
        {
            throw new NotImplementedException();
        }

        void TimerEventHandler(Object obj, EventArgs args)
        {
            
            if (Random.Next(100) < 25)
            {
                var ball = new Ball(400, 300, 10);
                Balls.Add(ball);
            }

            if (RBox.Count() < 2) 
            {
                var rbox = new Redbox(100 * Random.Next(1,8), 100* Random.Next(0,6));
                RBox.Add(rbox);
            }

            foreach (var ball in Balls)
            {
                ball.Move();
            }

            Form.Refresh();
}
void Draw(Object obj, PaintEventArgs args)
        {
            foreach (var ball in Balls)
            {
                ball.Draw(args.Graphics);
            }

            foreach (var rbox in RBox)
            {
                rbox.Draw(args.Graphics);
            }
}}

public class Engine
    {
        MainForm Form = new MainForm();
        Timer Timer = new Timer();
        List<Ball> Balls = new List<Ball>();
        List<Redbox> RBox = new List<Redbox>();
        Random Random = new Random();

        public void Run()
        {
            Form.Paint += Draw;
            Timer.Tick += TimerEventHandler;
            Timer.Interval = 1000/25;
            Timer.Start();

            Application.Run(Form);
        }

        private void Form_Paint(object sender, PaintEventArgs e)
        {
            throw new NotImplementedException();
        }

        void TimerEventHandler(Object obj, EventArgs args)
        {
            
            if (Random.Next(100) < 25)
            {
                var ball = new Ball(400, 300, 10);
                Balls.Add(ball);
            }

            if (RBox.Count() < 2) 
            {
                var rbox = new Redbox(100 * Random.Next(1,8), 100* Random.Next(0,6));
                RBox.Add(rbox);
            }

            foreach (var ball in Balls)
            {
                ball.Move();
            }

            Form.Refresh();
}
void Draw(Object obj, PaintEventArgs args)
        {
            foreach (var ball in Balls)
            {
                ball.Draw(args.Graphics);
            }

            foreach (var rbox in RBox)
            {
                rbox.Draw(args.Graphics);
            }
}}

I am doing an exercise about inheritance, interfaces and abstract classes. The Ball and engine class are both written already I am supposed to add obstacles and have the engine render both the balls and my added shapes

ero•2y ago

I don't see you using your interface anywhere W3S is always wrong The only stuff that site is competent about is HTML and CSS

XellezOP•2y ago

this says different sstuff nice yeah it seems I am not using my interface at all that link is safe right ?

ero•2y ago

I'm not sure any of that has to do with the implementation though Also I'd just use the Microsoft docs

XellezOP•2y ago

ero•2y ago

You're not really sharing your actual task, so it's hard to give any sort of advice The interface and the classes which implement the interface are perfectly fine It's just the implementation of the usages that aren't clear

XellezOP•2y ago

ok so if we use my interface to declare it It should be IObstacles RBox = new Redbox(10, 10);

ero•2y ago

Sure Not really how you'd use it That's why I wanted to see an example implementation; that's a bad one

XellezOP•2y ago

List<IObstacles> RBox = new List<IObstacles>(); is this also wrong ?

ero•2y ago

I'd change it to List<IObstacles> Obstacles = new(); So you save all of your instances in that one list That's a more proper use

XellezOP•2y ago

C# 7.3. Please use language version 9.0 or greater

ero•2y ago

Come on, don't just copy and paste

XellezOP•2y ago

ero•2y ago

I mean seriously, the error is so obvious, why even complain about it

XellezOP•2y ago

sorry I guess didnt know there where newer version of c# not supporting 2019 visual studio anymore

ero•2y ago

You don't need a new version

XellezOP•2y ago

I need .NET 7.x no ?

ero•2y ago

Just do = new List<IObstacle>(); like you did before

XellezOP•2y ago

nvm I am stupid

Thinker•2y ago

Yes but you should be using that anyway. Don't use 4.8 or whatever. Don't.

FusedQyou•2y ago

The basic idea of an interface is having the ability to define methods and properties that a class needs to implement. An interface usually consists of anything that is relevant to a certain "topic", you could say. In this case any class defining IObstacles must implement Draw, so every class relevant to obstacles would use this interface. The point of this is to create abstraction and to make it easier to define behaviour to anything related to obstacles. You can now use IObstacles as a type in your method, and it would expose Draw for you to use. There is much more you can do with interfaces

XellezOP•2y ago

@Ero I have a small question as I am creating a list of the type IObstacles would I be able to access position of any obstacles or do I need to create method that does that?

ero•2y ago

you will want to add a Position property to your interface

XellezOP•2y ago

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Is this the right way to implement an Interface