Task: Plot coordinate pairs




Go: package main

import (
  "fmt"
  "log"
  "os/exec"
)

var (
  x = []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
  y = []float64{2.7, 2.8, 31.4, 38.1, 58.0, 76.2, 100.5, 130.0, 149.3, 180.0}
)

func main() {
  g := exec.Command("gnuplot", "-persist")
  w, err := g.StdinPipe()
  if err != nil {
    log.Fatal(err)
  }
  if err = g.Start(); err != nil {
    log.Fatal(err)
  }
  fmt.Fprintln(w, "unset key; plot '-'")
  for i, xi := range x {
    fmt.Fprintf(w, "%d %f\n", xi, y[i])
  }
  fmt.Fprintln(w, "e")
  w.Close()
  g.Wait()
}


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();
    }
  }