Chapter 03 section 07 codes added.

Author: liuyubobobo

03-Probability-Simulation/06-Three-Gates-Problem/src/ThreeGatesExperiment.java

@@ -18,7 +18,7 @@ public void run(boolean changeDoor){
             if(play(changeDoor))
                 wins ++;
         System.out.println(changeDoor ? "Change" : "Not Change");
-        System.out.println("win rate:" + (double)wins/N);
+        System.out.println("winning rate:" + (double)wins/N);
     }
 
     private boolean play(boolean changeDoor){

03-Probability-Simulation/07-Winning-the-Prize/src/WinningPrize.java

@@ -0,0 +1,47 @@
+
+public class WinningPrize {
+
+    private double chance;
+    private int playTime;
+    private int N;
+
+    public WinningPrize(double chance, int playTime, int N){
+
+        if(chance < 0.0 || chance > 1.0)
+            throw new IllegalArgumentException("chance must be between 0 and 1!");
+
+        if(playTime <= 0 || N <= 0)
+            throw new IllegalArgumentException("playTime or N must be larger than 0!");
+
+        this.chance = chance;
+        this.playTime = playTime;
+        this.N = N;
+    }
+
+    public void run(){
+
+        int wins = 0;
+        for(int i = 0 ; i < N ; i ++)
+            if(play())
+                wins ++;
+
+        System.out.println("winning rate:" + (double)wins/N);
+    }
+
+    public boolean play(){
+        for(int i = 0 ; i < playTime ; i ++)
+            if(Math.random() < chance)
+                return true;
+        return false;
+    }
+
+    public static void main(String[] args) {
+
+        double chance = 0.2;
+        int playTime = 5;
+        int N = 1000000;
+
+        WinningPrize exp = new WinningPrize(chance, playTime, N);
+        exp.run();
+    }
+}