Task: Plot coordinate pairs

C: #include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <plot.h>

#define NP 10
double x[NP] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
double y[NP] = {2.7, 2.8, 31.4, 38.1, 58.0, 76.2, 100.5, 130.0, 149.3, 180.0};

void minmax(double *x, double *y,
	    double *minx, double *maxx, 
	    double *miny, double *maxy, int n)
{
  int i;

  *minx = *maxx = x[0];
  *miny = *maxy = y[0];
  for(i=1; i < n; i++) {
    if ( x[i] < *minx ) *minx = x[i];
    if ( x[i] > *maxx ) *maxx = x[i];
    if ( y[i] < *miny ) *miny = y[i];
    if ( y[i] > *maxy ) *maxy = y[i];
  }
}


#define YLAB_HEIGHT_F 0.1
#define XLAB_WIDTH_F 0.2  
#define XDIV (NP*1.0)
#define YDIV (NP*1.0)
#define EXTRA_W 0.01
#define EXTRA_H 0.01
#define DOTSCALE (1.0/150.0)

#define MAXLABLEN 32

#define PUSHSCALE(X,Y) pl_fscale((X),(Y))
#define POPSCALE(X,Y)  pl_fscale(1.0/(X), 1.0/(Y))
#define FMOVESCALE(X,Y) pl_fmove((X)/sx, (Y)/sy)

int main()
{
  int plotter, i;
  double minx, miny, maxx, maxy;
  double lx, ly;
  double xticstep, yticstep, nx, ny;
  double sx, sy;
  
  char labs[MAXLABLEN+1];

  plotter = pl_newpl("png", NULL, stdout, NULL);
  if ( plotter < 0 ) exit(1);
  pl_selectpl(plotter);
  if ( pl_openpl() < 0 ) exit(1);

  
  minmax(x, y, &minx, &maxx, &miny, &maxy, NP);

  lx = maxx - minx;
  ly = maxy - miny;
  pl_fspace(floor(minx) - XLAB_WIDTH_F * lx, floor(miny) - YLAB_HEIGHT_F * ly,
	    ceil(maxx) + EXTRA_W * lx, ceil(maxy) + EXTRA_H * ly);
  
  
  xticstep = (ceil(maxx) - floor(minx)) / XDIV;
  yticstep = (ceil(maxy) - floor(miny)) / YDIV;

  pl_flinewidth(0.25);

  
  if ( lx < ly ) {
    sx = lx/ly;
    sy = 1.0;
  } else {
    sx = 1.0;
    sy = ly/lx;
  }

  pl_erase();

  
  pl_fbox(floor(minx), floor(miny),
	  ceil(maxx), ceil(maxy));

  
  pl_fontname("HersheySerif");
  for(ny=floor(miny); ny < ceil(maxy); ny += yticstep) {
    pl_fline(floor(minx), ny, ceil(maxx), ny);
    snprintf(labs, MAXLABLEN, "%6.2lf", ny);
    FMOVESCALE(floor(minx) - XLAB_WIDTH_F * lx, ny);
    PUSHSCALE(sx,sy);
    pl_label(labs);
    POPSCALE(sx,sy);
  }
  for(nx=floor(minx); nx < ceil(maxx); nx += xticstep) {
    pl_fline(nx, floor(miny), nx, ceil(maxy));
    snprintf(labs, MAXLABLEN, "%6.2lf", nx);
    FMOVESCALE(nx, floor(miny));
    PUSHSCALE(sx,sy);
    pl_ftextangle(-90);
    pl_alabel('l', 'b', labs);
    POPSCALE(sx,sy);
  }

  
  pl_fillcolorname("red");
  pl_filltype(1);
  for(i=0; i < NP; i++)
  {
    pl_fbox(x[i] - lx * DOTSCALE, y[i] - ly * DOTSCALE,
            x[i] + lx * DOTSCALE, y[i] + ly * DOTSCALE);
  }

  pl_flushpl();
  pl_closepl();
}





Java:   import java.awt.*;
  import java.awt.event.*;
  import java.awt.geom.*;
  import javax.swing.JApplet;
  import javax.swing.JFrame;
  public class Plot2d extends JApplet {
    double[] xi;
    double[] yi;
    public Plot2d(double[] x, double[] y) {
        this.xi = x;
        this.yi = y;
    }
    public static double max(double[] t) {
        double maximum = t[0];   
        for (int i = 1; i < t.length; i++) {
            if (t[i] > maximum) {
                maximum = t[i];  
            }
        }
        return maximum;
    }
    public static double min(double[] t) {
        double minimum = t[0];
        for (int i = 1; i < t.length; i++) {
            if (t[i] < minimum) {
                minimum = t[i];
            }
        }
        return minimum;
    }
    public void init() {
        setBackground(Color.white);
        setForeground(Color.white);
    }
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setPaint(Color.black);
        int x0 = 70;
        int y0 = 10;
        int xm = 670;
        int ym = 410;
        int xspan = xm - x0;
        int yspan = ym - y0;
        double xmax = max(xi);
        double xmin = min(xi);
        double ymax = max(yi);
        double ymin = min(yi);
        g2.draw(new Line2D.Double(x0, ym, xm, ym));
        g2.draw(new Line2D.Double(x0, ym, x0, y0));
        for (int j = 0; j < 5; j++) {
            int interv = 4;
            g2.drawString("" + (j * (xmax - xmin) / interv + xmin), j * xspan / interv + x0 - 10, ym + 20);
            g2.drawString("" + (j * (ymax - ymin) / interv + ymin), x0 - 20 - (int) (9 * Math.log10(ymax)),
 ym - j * yspan / interv + y0 - 5);
            g2.draw(new Line2D.Double(j * xspan / interv + x0, ym, j * xspan / interv + x0, ym + 5));
            g2.draw(new Line2D.Double(x0 - 5, j * yspan / interv + y0, x0, j * yspan / interv + y0));
        }
        for (int i = 0; i < xi.length; i++) {
            int f = (int) ((xi[i] - xmin) * xspan / (xmax - xmin));
            int h = (int) (((ymax - ymin) - (yi[i] - ymin)) * yspan / (ymax - ymin));
            g2.drawString("o", x0 + f - 3, h + 14);
        }
        for (int i = 0; i < xi.length - 1; i++) {
            int f = (int) ((xi[i] - xmin) * xspan / (xmax - xmin));
            int f2 = (int) ((xi[i + 1] - xmin) * xspan / (xmax - xmin));
            int h = (int) (((ymax - ymin) - (yi[i] - ymin)) * yspan / (ymax - ymin));
            int h2 = (int) (((ymax - ymin) - (yi[i + 1] - ymin)) * yspan / (ymax - ymin));
            g2.draw(new Line2D.Double(f + x0, h + y0, f2 + x0, h2 + y0));
        }
    }
    public static void main(String args[]) {
        JFrame f = new JFrame("ShapesDemo2D");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        double[] r = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
        double[] t = {2.7, 2.8, 31.4, 38.1, 58.0, 76.2, 100.5, 130.0, 149.3, 180.09};
        JApplet applet = new Plot2d(r, t);
        f.getContentPane().add("Center", applet);
        applet.init();
        f.pack();
        f.setSize(new Dimension(720, 480));
        f.show();
    }
  }