Java学习笔记 7

-Java案例 P62-P65

案例一：买飞机票

//练习switch结构
public class Main{
    public static double calculate(double price,int month,String type){
        if(month>=5&&month<=10){
            switch(type){
                case "头等舱":
                price*=0.9;
                break;
            case "经济舱":
                price*=0.85;
                break;
            }
        }
        else{
            if(month>=5&&month<=10){
                switch(type){
                    case "头等舱":
                        price*=0.7;
                        break;
                    case "经济舱":
                        price*=0.65;
                        break;
                }

            }
        }
        return price;
    }

    public static void main(String args[]){
        double price=calculate(1000,8,"经济舱");
        System.out.println("该机票优惠后价格为"+price);
    }
}

案例二：开发验证码

//练习random和switch
import java.util.Random;
import java.util.Scanner;
public class Main{
    public static String CreateCode(int n){
        Random r=new Random();
        String code="";
        for(int i=0;i<n;i++){
            int type=r.nextInt(3);
            switch(type){
                case 0://数字字符
                    code+=r.nextInt(10);
                    break;
                case 1://大写字母
                    code+=(char)(r.nextInt(26)+65);
                    break;
                case 2://小写字母
                    code+=(char)(r.nextInt(26)+97);
                    break;
            }
        }
        return code;
    }
    public static void main(String args[]){
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        System.out.println(CreateCode(n));
    }
}

案例三：评委打分

//练习数组使用
import java.util.Scanner;
public class Main{
    public static void main(String args[]){
        int n;
        Scanner sc=new Scanner(System.in);
        n=sc.nextInt();
        int [] score=new int [n+5];
        for(int i=0;i<n;i++){
            score[i]=sc.nextInt();
        }
        int max=score[0],min=score[0],sum=0;
        for(int i=0;i<n;i++){
            sum+=score[i];
            if(score[i]>max) max=score[i];
            if(score[i]<min) min=score[i];
        }
        sum-=max;sum-=min;
        System.out.println(1.0*sum/(n-2));
    }
}

案例四：数字加密

//找到了类似于vector的东西，array list的语法更繁琐，但目前来看vector有的功能它也有

import java.util.*;

public class Main{
    public static void main(String args[]){
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        List <Integer> num=new ArrayList<Integer>();
        while(n!=0) {
            num.add(n%10);
            n/=10;
        }
        for(int i=0;i<num.size();i++){
            num.set(i,(num.get(i)+5)%10);
        }
        for(int i=0;i<num.size();i++) System.out.print(num.get(i));
    }
}

案例五：数组拷贝

    public static int[] copyarr(int[] arr){
        int[] ans=new int[arr.length];
        for(int i=0;i<arr.length;i++) ans[i]=arr[i];
        return ans;
    }

案例六：抢红包

import java.util.*;

public class Main{
    public static void gift(int[] money){
        Scanner sc=new Scanner(System.in);
        Random r=new Random();
        for(int i= money.length;i>0;i--){
            System.out.println("输入任意字符开始抽奖！");
            sc.nextInt();
            int idx=r.nextInt(i);
            System.out.println("恭喜抽中"+money[idx]+"元！");
            money[idx]=money[i-1];
        }
    }
    public static void main(String args[]){
        int[] money={9,666,188,520,999};
        gift(money);
    }
}