Java 面试习题

机票购买优惠折扣

实现代码：

// price 机票原价
    // month 购买机票的月份
    // flag  购买的是头等舱(0)还是商务舱(1)
    public static int buyPlane(int price, int month, int flag) {
        if (month >= 5 && month <= 10) {
            switch (flag) {
                case 0:
                    price = (int) (price * 0.9);
                    break;
                case 1:
                    price = (int) (price * 0.85);
                    break;
            }
        } else if ((month >= 1 && month <= 4) || (month >= 11 && month <= 12)) {
            switch (flag) {
                case 0:
                    price = (int) (price * 0.7);
                    break;
                case 1:
                    price = (int) (price * 0.65);
                    break;
            }
        } else {
            System.out.println("没有这个月份");
        }
        return price;
    }

找质数

质数：除了1和他本身之外不能被其他整除的数

案例： 找出101~200之间是质数的个数

代码：

// 找质数
    public static int findPrimecoin() {
        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) {
                count++;
            }
        }
        return count;
    }

生成验证码

规则：
1.长度5
2.前4位是字母，不管是大写还是小写
3.最后一位是数字

//生成验证码
    // Acoll码
    // a -- 97
    // A -- 65
    public static String createVerification() {
        //将小写字母和大写字母一起放入一个集合中
        char[] verification = new char[52];
        for (int i = 0; i < verification.length; i++) {
            if (i <= 25) {
                verification[i] = (char) (97 + i);
            } else {
                verification[i] = (char) (65 + i - 26);
            }
        }
        //随机生成4个字母
        Random r = new Random();
        String result = "";
        for (int i = 0; i < 4; i++) {
            int randomIndex = r.nextInt(verification.length);
            result += verification[randomIndex];
        }
        //随机生成数字
        int number = r.nextInt(10);
        result += number;
        return result;
    }

评委打分

public static int judgeMark() {
        int[] judgeNumber = new int[6];
        Scanner sc = new Scanner(System.in);
        for (int i = 0; i < judgeNumber.length; ) {
            System.out.println("请输入第" + (i + 1) + "位评委分数");
            int result = sc.nextInt();
            if (result >= 0 && result <= 100) {
                judgeNumber[i] = result;
                i++;
            } else {
                System.out.println("评委的分数录入失败");
            }
        }
        //拿到评分的max和min值
        int max = judgeNumber[0];
        int min = judgeNumber[0];
        for (int i = 0; i < judgeNumber.length; i++) {
            if (judgeNumber[i] > max) {
                max = judgeNumber[i];
            }
            if (judgeNumber[i] < min) {
                min = judgeNumber[i];
            }
        }

        //算平均值
        int svg = 0;
        for (int i = 0; i < judgeNumber.length; i++) {
            svg += judgeNumber[i];
        }
        svg = (svg - max - min) / 4;
        return svg;

    }

密码加密

//密码加密
    public static void gradeEncryption(){
        int [] arr = new int[4];
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入密码");
        for (int i = 0; i < arr.length; i++) {
            int result = sc.nextInt();
            arr[i] = result;
        }
        //对数组中的元素中进行加密处理
        for (int i = 0; i < arr.length; i++) {
            arr[i] = (arr[i]+5)%10;
        }
        //将数组中的元素进行倒序
        for (int i = 0,j=arr.length-1; i < j; i++,j--) {
            int number = arr[i];
            arr[i] = arr[j];
            arr[j] = number;
        }
        //将加密后的代码包裹起来
        String result = "";
        for (int i = 0; i < arr.length; i++) {
            result += arr[i];
        }
        System.out.println(result);
    }