Java数组

Arrays: 用于处理数组的工具类
常见的方法：

        //默认升序排序
        Arrays.sort(numberList);
        for (int i : numberList) {
            System.out.println(i);
        }
        //指定从哪到哪索引位置排序,例如[0,4) ,注意区间
        Arrays.sort(numberList,0,4);
        for (int i : numberList) {
            System.out.println(i);
        }
        //填充,用5去填充数组
        Arrays.fill(numberList,5);
        for (int i : numberList) {
            System.out.println(i);
        }
        //填充某个区间，用索引，例如[0,3)用5去填充
        Arrays.fill(numberList,0,3,5);
        for (int i : numberList) {
            System.out.println(i);
        }
        //复制数组，并指定新数组长度
        int[] newList = Arrays.copyOf(numberList,5);
        for (int i : newList) {
            System.out.println(i);
        }

注意： 使用二分查找法，数组是需要提前排序的

        //二分搜索法,例如查找34在数组中的索引
        Arrays.sort(numberList);
        int index = Arrays.binarySearch(numberList,34);
        System.out.println(index);

双色球游戏：
中奖规则

        Random r = new Random();
        int[] comRed = new int[6];
        //蓝球号码产生
        int comBlue = r.nextInt(16) + 1;
        for (int i = 0;i < comRed.length;i++){
            comRed[i] = r.nextInt(33) + 1;
            //判断号码是否重复，重复在随机产生
            for (int j = 0;j < i;j++){
                if (comRed[j] == comRed[i]){
                    i--;
                    break;
                }
            }
        }
        //购买者红球号码
        int[] userRed = new int[6];
        //购买者蓝球号码
        int userBlue;
        for (int i = 0;i < 6;i++){
            System.out.println("请输入购买的第" +(i + 1)+ "注红球号码");
            userRed[i] = sc.nextInt();
            if (userRed[i] < 1||userRed[i]>33){
                System.out.println("红球号码范围[1,33]");
                System.out.println("请输入购买的第" +(i + 1)+ "注红球号码");
                userRed[i] = sc.nextInt();
            }
            for (int j = 0;j < i;j++){
                if (userRed[j] == userRed[i]){
                    System.out.println("请勿购买重复号码!!");
                    i--;
                    break;
                }
            }
        }

        while (true){
            System.out.println("请输入购买蓝球号码：");
            userBlue = sc.nextInt();
            if (userBlue >= 1&&userBlue<=16){
                break;
            }
            System.out.println("蓝球号码范围为[1,16]!!");
        }
        System.out.println("红球开奖号码为:");
        for (int i : comRed) {
            Thread.sleep(1000);
            System.out.print(i + "t");
        }
        System.out.println();
        System.out.println("蓝球开奖号码为：");
        System.out.println(comBlue);
        int redCount = 0,blueCount = 0;
        if (comBlue == userBlue){
            blueCount = 1;
        }
        for (int k : comRed) {
            for (int i : userRed) {
                if (k == i) {
                    redCount++;
                }
            }
        }
        if (redCount == 6&&blueCount == 1){
            System.out.println("恭喜中了一等奖!!!");
        }else if(redCount == 6){
            System.out.println("恭喜中了二等奖!!!");
        }else if (redCount == 5&&blueCount == 1){
            System.out.println("恭喜中了三等奖!!!");
        }else if (redCount == 5||(redCount == 4&&blueCount == 1)){
            System.out.println("恭喜中了四等奖!!!");
        }else if (redCount == 4||(redCount == 3&&blueCount == 1)){
            System.out.println("恭喜中了五等奖!!!");
        }else if ((redCount == 2&&blueCount == 1)||(redCount == 1&&blueCount == 1)||(redCount == 0&&blueCount == 1)){
            System.out.println("恭喜中了六等奖!!!");
        }else {
            System.out.println("很遗憾!!!");
        }