LACS2013-FunctionMode.java

//FunctionMode.java MrG 2013.0521
public class FunctionMode
{
    private double a;
    private double b;
    private double c;

    public FunctionMode(double a, double b, double c)
    {
        this.a = a;
        this.b = b;
        this.c = c;
    }

    public void axes(double xMin, double xMax, double yMin, double yMax)
    {
        StdDraw.setPenRadius(.005);
        StdDraw.line(0,yMin,0,yMax);
        StdDraw.line(xMin,0,xMax,0);
        StdDraw.text(xMax,-1,"x");
        StdDraw.text(1,yMax,"y");
    }

    public void plot(double xMin, double xMax)
    {
        StdDraw.setPenRadius(.01);
        StdDraw.setPenColor(StdDraw.GREEN);
        double x0 = xMin;
        double y0 = a*xMin*xMin + b*xMin + c;
        for(double xn=xMin; xn<=xMax; xn+=(xMax-xMin)/100)
        {
            double yn = a*xn*xn + b*xn + c;
            StdDraw.line(x0,y0,xn,yn);
            x0=xn;
            y0=yn;
        }
    }
}