Algorithmen und Programmierung II

Übungsblatt 6 - Musterlösung

public class Eintrag {

    String name;
    int nummer;
    Eintrag naechster;
    
    Eintrag(String name, int nummer, Eintrag naechster) {
        this.name = name;
        this.nummer = nummer;
        this.naechster = naechster;
    }
    
    int nummer(String name) {
        Eintrag test = this;
        while(test != null && name.compareTo(test.name) > 0)
            test = test.naechster;
        if (test == null || name.compareTo(test.name) != 0)
            return 0;
        return test.nummer;
    }
    
    void eintragen(String name, int nummer) {
        if (name.compareTo(this.name) < 0) { // Eintrag vor dem ersten
            this.naechster = new Eintrag(this.name, this.nummer, naechster);
            this.name = name;
            this.nummer = nummer;
            return;
        }
        Eintrag test = this, vorg = null;
        while(test != null && name.compareTo(test.name) > 0) {
            vorg = test;
            test = test.naechster;
        }
        if (test != null && name.compareTo(test.name) == 0)
            test.nummer = nummer;
        else
            vorg.naechster = new Eintrag(name, nummer, test);
    }
}

public class Weekday {

    String day;
    Weekday next;
    
    Weekday(String day, Weekday next) {
        this.day = day; this.next = next;
    }
    
    static Weekday current;

    static {
        current   = new Weekday("Samstag", null);
        Weekday d = new Weekday("Freitag", current);
        d = new Weekday("Donnerstag", d);
        d = new Weekday("Mittwoch", d);
        d = new Weekday("Dienstag", d);
        d = new Weekday("Montag", d);
        d = new Weekday("Sonntag", d);
        current.next = d;
    }

    static String next() {
        return (current = current.next).day;
    }
}

public class Triangle {

    public static void main(String[] args) {
        int width = 640;
        int height = 480;
        DrawingWindow df = new DrawingWindow(width, height);

        Point a = new Point(100, 100);
        Point b = new Point(300, 100);
        Point c = new Point(200, 300);

        df.addLine(new Line(a, b));
        df.addLine(new Line(b, c));
        df.addLine(new Line(c, a));

        int axstep, aystep, bxstep, bystep, cxstep, cystep;
        axstep = aystep = cxstep = cystep = 2;
        bxstep = bystep = 3;

        while (true) {
            if (a.x + axstep > width  || a.x + axstep < 0) axstep = -axstep;
            if (a.y + aystep > height || a.y + aystep < 0) aystep = -aystep;
            if (b.x + bxstep > width  || b.x + bxstep < 0) bxstep = -bxstep;
            if (b.y + bystep > height || b.y + bystep < 0) bystep = -bystep;
            if (c.x + cxstep > width  || c.x + cxstep < 0) cxstep = -cxstep;
            if (c.y + cystep > height || c.y + cystep < 0) cystep = -cystep;

            a.x += axstep;
            a.y += aystep;
            b.x += bxstep;
            b.y += bystep;
            c.x += cxstep;
            c.y += cystep;

            df.update();
        }
    }
}