package demo2;
import java.util.Arrays;
import java.util.Random;
/**
* 系统作为彩票双色球生成器，模拟机选一注双色球的彩票号码：
* 1、需要从“01”到“32”中随机选择出6个数字作为红色球且这6个数字不能重复；
* 2、并从”01”到”07”中随机选择一个数字作为蓝色球；
* 3、7个数字合到一起作为一注双色球彩票的号码；
*/
public class DoubleBall {
public static void main(String[] args) {
String[] RED_BALLS = { "01", "02", "03", "04", "05", "06", "07", "08",
"09", "10", "11", "12", "13", "14", "15", "16", "17", "18",
"19", "20", "21", "22", "23", "24", "25", "26", "27", "28",
"29", "30", "31", "32" };
String[] BLUE_BALLS = { "01", "02", "03", "04", "05", "06", "07" };
boolean[] redFlags = new boolean[RED_BALLS.length];
String[] redBalls = new String[6];
String blueBall;
Random ran = new Random();
// red
for (int i = 0; i < redBalls.length; i++) {
int index;
do {
index = ran.nextInt(RED_BALLS.length);
} while (redFlags[index]);
/**
* redFlags[index]用途：
* 当redFlags[index]=true表示已经重复，所以你需要
* 再执行do当中的代码重新获取index
*/
redBalls[i] = RED_BALLS[index];
redFlags[index] = true;
}
// blue
blueBall = BLUE_BALLS[ran.nextInt(BLUE_BALLS.length)];
Arrays.sort(redBalls);
System.out.println("**********本期开奖**********");
System.out.println("红球: ");
for (int i = 0; i < redBalls.length; i++) {
System.out.print("(" + redBalls[i] + ") ");
}
System.out.println();
System.out.println("篮球: ");
System.out.print("(" + blueBall + ") ");
}
}