判断质数Java代码

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public static void main(String[] args) {
    //判断200-500有多少质数
    int count = 0;
    for (int i = 101; i < 200; i++) {
        boolean flag = true;
        for (int j = 2; j < i; j++) {
            if (i % j == 0) {
                flag = false;
                break;
            }
        }
        if (flag) {
            System.out.println("数字" + i + "是质数");
            count++;
        }
    }
    System.out.println("质数共计"+count);
}

验证码Java代码

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    public static void main(String[] args) {
        //前四位是大写字母与小写字母的随机组合，最后一位是随机数字
        //先定义一个字符数组
        char[] chars = new char[52];
        for (int i = 0; i < chars.length; i++) {
            if (i < 26) {
                chars[i] = (char) ('a' + i);
            } else {
                chars[i] = (char) ('A' + i - 26);
            }
            // System.out.print(chars[i]);
        }
//        for (int i = 0; i < chars.length; i++) {
//            System.out.print(chars[i] + " ");
//        }
        String result = "";
        Random random = new Random();
        for (int i = 0; i < 4; i++) {
            //拿到四次随机的字符
            int j = random.nextInt(chars.length);
            result = result + chars[j];
        }
        //随机生成0-9的数字
        int number = random.nextInt(10);
        System.out.print(result + number);
    }

飞机买票Java

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 public static void main(String[] args) {
        /*机票按照淡旺季进行收费 输入原价  月份 和头等舱或者经济舱进行判断
        旺季（5-9）头等舱九折 经济舱8.5折，淡季 10月到来年的四月头等舱7折 经济舱6.5折
         */
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入票价：");
        int ticket = sc.nextInt();
        System.out.println("请输入月份：");
        int month = sc.nextInt();
        System.out.println("请输入舱位  0表示头等舱   1表示经济舱");
        int seat = sc.nextInt();
        if (month >= 5 && month <= 9) {
//            ticket = getTicket(seat, ticket, 0.9, 0.85);
            ticket = getTicket(seat, ticket, 0.9, 0.85);
        } else if ((month >= 1 && month <= 4) || (month >= 10 && month <= 12)) {
            ticket = getTicket(seat, ticket, 0.7, 0.65);
//            ticket = getTicket(seat, ticket, 0.7, 0.65);
        } else {
            System.out.println("输入不合法!!");
        }
        System.out.println("打完折的票价为：" + ticket);
    }

    public static int getTicket(int seat, int ticket, double x, double x1) {
        if (seat == 0) {
            ticket = (int) (ticket * x);
        } else {
            ticket = (int) (ticket * x1);
        }
        return ticket;
    }

数组复制java

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public static void main(String[] args) {
    int[] arr = {1, 3, 2, 4, 5, 6, 3, 1, 13, 3, 4, 55, 6, 8};
    int[] newArr = new int[arr.length];
    for (int i = 0; i < arr.length; i++) {
        //i是索引值  arr[i]是值
        newArr[i] = arr[i];
    }

    for (int i = 0; i < newArr.length; i++) {
        System.out.print(newArr[i] + " ");
    }
}

评委打分

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public static void main(String[] args) {
    //去掉一个最高分 去掉一个最低分 求其平均数共计六个评委分数在0-100之间

    int[] scores = getScore();
    int max = getMax(scores);
    int min = getMin(scores);
    int avg = (getSum(scores) - max - min) / (scores.length - 2);
    System.out.println("该选手的最终成绩："+avg);
}

public static int[] getScore() {
    int[] arr = new int[6];
    Scanner scanner = new Scanner(System.in);
    for (int i = 0; i < arr.length; ) {
        System.out.println("请输入六组成绩：");
        int score = scanner.nextInt();
        if (score >= 0 && score <= 100) {
            arr[i] = score;
            i++;
        } else {
            System.out.println("成绩录入不合法，请重新录入：当前的i为"+i);
        }
    }
    return arr;
}

//寻找最大值
public static int getMax(int[] arr) {
    int max = arr[0];
    for (int i = 1; i < arr.length; i++) {
        if (arr[i] > max) {
            max = arr[i];
        }
    }
    return max;
}

//寻找最小值
public static int getMin(int[] arr) {
    int min = arr[0];
    for (int i = 1; i < arr.length; i++) {
        if (arr[i] < min) {
            min = arr[i];
        }
    }
    return min;
}

//求数组元素之和
public static int getSum(int[] arr) {
    int sum = 0;
    for (int j : arr) {
        sum = sum + j;
    }
    return sum;
}

数字加解密

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public static void main(String[] args) {
        //对数字进行加密解密操作，位数加5 在对10取余 然后 翻转
        int[] arr = {1, 9, 8, 3};
        //进行加5操作
        for (int i = 0; i < arr.length; i++) {
            arr[i] = arr[i] + 5;
//            System.out.print(arr[i] + " ");
        }
        //对10取余数操作
        for (int i = 0; i < arr.length; i++) {
            arr[i] = arr[i] % 10;
        }
        for (int i = 0, j = arr.length - 1; i < j; i++, j--) {
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
//        for (int i = 0; i < arr.length; i++) {
//            System.out.print(arr[i] + " ");
//        }
        //对数字进行拼接
        int number=0;
        for (int i = 0; i < arr.length; i++) {
            number=number*10+arr[i];
        }
        System.out.println(number);
    }
    ===================================================
        public static void main(String[] args) {
        //请输入需要解密的数字
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入需要解密的数字：");
        int number = sc.nextInt();
        int temp = number;
        //计算数组的大小
        int count = 0;
        while (number != 0) {
            number = number / 10;
            count++;
        }
        int[] arr = new int[count];
        int index = arr.length-1;
        while (temp != 0) {
            int ge = temp % 10;
            arr[index] = ge;
            index--;
            temp = temp / 10;
        }
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
    }
    =================================================
     public static void main(String[] args) {
        //解密操作先翻转  后加五 对10反向取余
        int[] arr = {8, 3, 4, 6};
        for (int i = 0, j = arr.length - 1; i < j; i++, j--) {
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
        //由于加密加五对10取余 故0-4＋10,5-9不变；
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] >= 0 && arr[i] <= 4) {
                arr[i] += 10;
            }
        }
        for (int i = 0; i < arr.length; i++) {
            arr[i] -= 5;
        }
        int number = 0;
        for (int i = 0; i < arr.length; i++) {
            number = number * 10 + arr[i];
        }
        System.out.println("解密后的数字：" + number);
    }

抽奖

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public static void main(String[] args) {
       int[] arr = {1000, 23, 8, 54, 32, 12, 56, 7};
       int[] arr1 = new int[arr.length];
       //抽奖
       Random r = new Random();
       for (int i = 0; i < arr.length; ) {
           //获取随机索引
           int index = r.nextInt(arr.length);
           int key = arr[index];
           boolean flag = getComment(arr1, key);
           if (!flag) {
               //将奖项添加到新数组中
               arr1[i] = key;
               i++;
           }
       }
       for (int i = 0; i < arr1.length; i++) {
           System.out.println(arr1[i]);
       }

   }

   //判断key在数组中是否存在
   public static boolean getComment(int[] arr, int key) {
       for (int i = 0; i < arr.length; i++) {
           if (arr[i] == key) {
               return true;
           }
       }
       return false;
   }

抽奖优化

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public static void main(String[] args) {
    //抽奖优化 打乱数组在输出
    Random r = new Random();
    int[] arr = {1000, 23, 8, 54, 32, 12, 56, 7};
    for (int i = 0; i < arr.length; i++) {
        //获取索引值
        int index = r.nextInt(arr.length);
        int temp = arr[i];
        arr[i] = arr[index];
        arr[index] = temp;
    }
    for (int i = 0; i < arr.length; i++) {
        System.out.println(arr[i]);
    }
}

双色球系统java

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//6个红球和一个蓝色球 红球的号码为1-33 篮球的1-16  且红色不允重复
public static void main(String[] args) {
    //1 创建出中奖号码
    int[] arr = createNumber();
    System.out.println("====================");
    for (int i = 0; i < arr.length; i++) {
        System.out.print(arr[i] + " ");
    }
    System.out.println();
    System.out.println("---------------------");
    //2 用户输入中奖号码
    int[] userArr = userNumber();
    for (int i = 0; i < userArr.length; i++) {
        System.out.print(userArr[i]+" ");
    }
    //3 判断用户中奖情况
    //红球中奖情况
    int redCount = 0;
    int blueConut = 0;
    for (int i = 0; i < userArr.length - 1; i++) {
        //减一判断的是蓝球
        int redNumber = userArr[i];
        for (int j = 0; j < arr.length - 1; j++) {
            if (redNumber == arr[j]) {
                redCount++;
                break;
            }
        }
    }
    //判断蓝球
    int blueNumber = userArr[userArr.length - 1];
    if (blueNumber == arr[arr.length - 1]) {
        blueConut++;
    }
    System.out.println("蓝球中奖个数：" + blueConut + "  " + "红球中奖个数： " + redCount);

    //根据红蓝球个数判断中奖情况
    if (redCount == 6 && blueConut == 1) {
        System.out.println("恭喜你中奖一千万！！");
    }
    else if (redCount == 6 && blueConut == 0) {
        System.out.println("恭喜你中奖500万！！");
    }
    else if ((redCount == 4 && blueConut == 1) || (redCount == 5 && blueConut == 0)) {
        System.out.println("恭喜你中奖2万！！");
    }
    else if (redCount == 5 && blueConut == 1) {
        System.out.println("恭喜你中奖200万！！");
    }
    else if ((redCount == 2 && blueConut == 1)
            || (redCount == 2 && blueConut == 0)
            || (redCount == 1 && blueConut == 1)
    ){
        System.out.println("恭喜你中奖10块！！");
    }
    else {
        System.out.println("谢谢惠顾！！");
    }
}

public static int[] createNumber() {
    int[] arr = new int[7];
    Random r = new Random();
    //首先生成红球中奖号码
    for (int i = 0; i < arr.length - 1; ) {
        int redNumber = r.nextInt(33) + 1;
        boolean falg = contains(arr, redNumber);
        if (!falg) {
            arr[i] = redNumber;
            i++;
        }
    }
    int blueNumber = r.nextInt(16) + 1;
    arr[arr.length - 1] = blueNumber;
    return arr;
}

//判断红色小球数字是否重复
public static boolean contains(int[] arr, int key) {
    for (int i = 0; i < arr.length; i++) {
        if (arr[i] == key) {
            return true;
        }
    }
    return false;
}

//用户输入号码
public static int[] userNumber() {
    int[] arr = new int[7];
    Scanner sc = new Scanner(System.in);
    //首先生成红球中奖号码
    for (int i = 0; i < arr.length - 1; ) {
        System.out.print("请输入第" + (i + 1) + "个号码：");
        int redNumber = sc.nextInt();
        if (redNumber >= 1 && redNumber <= 33) {
            //判断录入号码是否重复
            boolean flag = contains(arr, redNumber);
            if (!flag) {
                arr[i] = redNumber;
                i++;
            } else {
                System.out.println("当前录入号码已经存在！请重新录入：");
            }
        } else {
            System.out.println("录入超出范围（1-33），请重新录入！");
        }
    }
    //输入蓝球号码
    System.out.println("请输入蓝球号码：");
    while (true) {
        int blueNumber = sc.nextInt();
        if (blueNumber >= 1 && blueNumber <= 16) {
            arr[arr.length - 1] = blueNumber;
            break;
        }
        else{
            System.out.println("当前蓝球录入超出范围,请重新录入：");
        }
    }
    return arr;
}