1 飞机票

代码实现：

import java.util.Scanner;
public class F1 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("请输入票价：  ");
        double jia = input.nextDouble();
        System.out.print("请输入月份：  ");
        int yue = input.nextInt();
        System.out.print("请输入你所坐飞机舱（经济舱或头等舱）  ");
        String can = input.next();
        methodjia(jia,yue,can);
    }
    private static void methodjia(double jia, int yue, String can) {
        if (yue>=5 && yue<=10){
            if (can.equals("经济舱")){
                jia=jia*0.85;
            }else if(can.equals("头等舱")) {
                jia = jia * 0.9;
            }else
                System.out.println("输入错误");
                return;
        } else if((yue>10 && yue<=12) || (yue<5 && yue>0)){
            if (can.equals("头等舱")){
                jia=jia*0.7;
            }else if(can.equals("经济舱")){
                jia=jia*0.65;}
            else
                System.out.println("输入错误");
                return;
        } else if(yue<0||yue>12){
        System.out.println("错误");
        return;}
        System.out.println(jia);
    }
}

2 生成一个五位数验证码

代码实现：

import java.util.Random;

public class Yzm {
    public static void main(String[] args) {

        char []arr = new char[52];
        Random rand = new Random();
        for (int i = 0; i < 26; i++) {
            arr[i] = (char) (65+i);
        }
        for (int i = 0; i <26; i++) {
            arr[i+26] = (char) (97+i);
        }
        String s ="";
        for (int i = 0; i < 4; i++) {
            char k = arr[rand.nextInt(52)];
            s=s+k;
        }

        int i = rand.nextInt(10);
        s=s+i;
        System.out.println(s);

    }
}

3 数字加密

代码实现：

import java.util.Scanner;

public class Jm {
    public static void main(String[] args) {
        int num = new Scanner(System.in).nextInt();//输入一个数组

        jiami(intToArray3(num));//方法调用

    }
    private static void jiami(int[] arr) {//加密方法每个位数+5，每个位数对10取模，再倒序

        for (int i = 0; i < arr.length; i++) {
            arr[i]+=5;
        }
        for (int i = 0; i < arr.length; 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;
        }
        int num = 0;
        for (int i = 0; i < arr.length; i++) {
            num= num*10+arr[i];
        }
        System.out.println(num);
    }
    private static int[] intToArray3(int num){
        int len = String.valueOf(num).length();//得到这个数的长度以便创建数组
        int[] resultArray = new int[len];//创建数组
        while (num != 0){//给数组一一赋值
            resultArray[len-1] = num % 10;
            num = num / 10;
            len--;
        }
        return resultArray;//返回位数组成的数组
    }
}