The Shape Example in D

Contributed by Leonardo

Code for D

File: shapes.d

import std.stdio: writefln;

abstract class Shape {
    private int x_, y_;

    // constructor
    this(int newx, int newy) {
        this.x = newx;
        this.y = newy;
    }

    // accessors for x & y coordinates
    public int x() { return this.x_; }
    public int y() { return this.y_; }
    public void x(int newx) { this.x_ = newx; }
    public void y(int newy) { this.y_ = newy; }

    // move the x & y coordinates
    public void moveTo(int newx, int newy) {
        this.x = newx;
        this.y = newy;
    }

    public void rMoveTo(int deltax, int deltay) {
        moveTo(deltax + this.x, deltay + this.y);
    }

    // virtual routine - draw the shape
    public void draw();
}


class Rectangle: Shape {
    private int width_, height_;

    // constructor
    this(int newx, int newy, int newWidth, int newHeight) {
        super(newx, newy);
        this.width = newWidth;
        this.height = newHeight;
    }

    // accessors for width & height
    public int width() { return this.width_; }
    public int height() { return this.height_; }
    public void width(int newWidth) { this.width_ = newWidth; }
    public void height(int newHeight) { this.height_ = newHeight; }

    // draw the rectangle
    public void draw() {
        writefln("Drawing a Rectangle at:(%d,%d), Width %d, Height %d",
                 this.x, this.y, this.width, this.height);
    }
}


class Circle: Shape {
    private int radius_;

    // constructor
    this(int newx, int newy, int newRadius) {
        super(newx, newy);
        this.radius = newRadius;
    }

    // accessors for the radius
    public int radius() { return this.radius_; }
    public void radius(int newRadius) { this.radius_ = newRadius; }

    // draw the circle
    public void draw() {
        writefln("Drawing a Circle at:(%d,%d), Radius %d", this.x, this.y, this.radius);
    }
}


void main() {
    Shape[] scribble;

    // create some shape instances
    scribble ~= new Rectangle(10, 20, 5, 6);
    scribble ~= new Circle(15, 25, 8);

    // iterate through the list and handle shapes polymorphically
    foreach (shape; scribble) {
        shape.draw();
        shape.rMoveTo(100, 100);
        shape.draw();
    }

    // call a rectangle specific function
    auto rect = new Rectangle(0, 0, 15, 15);
    rect.width = 30;
    rect.draw();
}

Output

Drawing a Rectangle at:(10,20), Width 5, Height 6
Drawing a Rectangle at:(110,120), Width 5, Height 6
Drawing a Circle at:(15,25), Radius 8
Drawing a Circle at:(115,125), Radius 8
Drawing a Rectangle at:(0,0), Width 30, Height 15