a bug--do...while()_do t = rand.nextint(flavors.length)-优快云博客

本文介绍了一个使用Java实现的随机冰淇淋口味选择器程序。该程序通过随机算法从预定义的口味列表中选取不重复的口味组合。文章指出程序存在小概率死循环的bug，并讨论了其触发条件。

import java.util.*;
public class IceCream
{
private static Random rand=new Random();
public static final String[] flavors={
  "Chocolate","Strawberry","Vanilla Fudge Swirl",
   "Mint Chip","Mocha Almond Fudge","Rum Raisin",
   "Praline Cream","Mud Pie"
};
public static String[] flavorSet(int n){
  String[] results=new String[n];
  boolean[] picked=new boolean[flavors.length];
  for(int i=0;i<n;i++){
   int t;
   do
     t=rand.nextInt(flavors.length);
   while(picked[t]);
   results[i]=flavors[t];
   picked[t]=true;
  }
  return results;
}
public static void main(String[] args)
{
  for(int i=0;i<20;i++){
   System.out.println("flavorSet("+i+")=");
   String[] f1=flavorSet(flavors.length);
   for(int j=0;j<f1.length;j++)
    System.out.println("/t"+f1[j]);
  }
}
}