page59-一种能够累加数据的ADT(可视化版本) [可用于数据挖掘可视化工具]

 1 public class VisualAccumulator {
 2     
 3     private double total;
 4     private int N;
 5 
 6     public VisualAccumulator(int trials , double max){
 7         
 8         StdDraw.setXscale(0, trials);
 9         StdDraw.setYscale(0, max);
10         StdDraw.setPenRadius(.005);
11     }
12     
13     public void addDataValue(double val){
14         
15         N ++;
16         total += val;
17         StdDraw.setPenColor(StdDraw.DARK_GRAY);
18         StdDraw.point(N, val);
19         StdDraw.setPenColor(StdDraw.RED);
20         StdDraw.point(N, total/N);
21         
22     }
23     public double mean(){
24         return total/N;
25     }
26     public String toString(){
27         return "mean  (" + N + "values: )" + String.format("%7.5f", mean());
28     }
29 }

 1 public class TestVisualAccumulator {
 2 
 3     
 4     public static void main(String[] args) {
 5 
 6         int T = Integer.parseInt(args[0]);
 7         VisualAccumulator a = new VisualAccumulator(T, 1.0);
 8         for (int t = 0; t < T; t++) 
 9             a.addDataValue(StdRandom.uniform());
10         StdOut.println(a);
11     }                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
12 }