2020.7.9

一、今日学习内容

1、对第二章的综合案例进行了验证

（1）扑克牌

public class CardDemo {

    public static void main(String[] args) {
        String[] suit= {"梅花","方块","红桃","黑桃"};
        String[] number= {"A","2","3","4","5","6","7","8","9","10","J","Q","k"};
        String[] cards=new String[64];
        for(int i=0;i<cards.length-2;i++) {
            cards[i]=suit[i%suit.length]+number[i%number.length];
        }
        cards[cards.length-2]="大王";
        cards[cards.length-1]="小王";
        for(int i=0;i<cards.length;i++) {
            System.out.print(cards[i]+"	");
            if(i%13==0&&i!=0)System.out.println();
        }
    }

}

        （2）ATM机取钱

import java.util.Scanner;
public class ATM {
    public static void main(String[] args) {
        System.out.print("请输入密码：");
        Scanner con=new Scanner(System.in);
        String line=con.nextLine();
        if(line.equals("1234")) {
            System.out.println("1、取款");
            System.out.println("2、退出");
            int num=con.nextInt();
            switch(num) {
            case 1:
                System.out.println("1、取款100");
                System.out.println("2、取款200");
                System.out.println("3、取款500");
                System.out.println("4、其他");
                int money=con.nextInt();
                switch(money) {
                case 1:
                    System.out.println("取款100！");
                    break;
                case 2:
                    System.out.println("取款200！");
                    break;
                case 3:
                    System.out.println("取款500！");
                    break;
                case 4:
                    System.out.println("请输入取款金额:");
                    int other=con.nextInt();
                    System.out.println("取款"+other+"元！");
                    break;
                }
                break;
            case 2:
                System.out.println("欢迎下次光临！谢谢！");
                break;
                
            }
        }

    }

}

2、学习了第三章的内容值的比较

（1）值得比较

          最大值：

public class MaxDemo {
    public static void main(String[] args) {
        int a=30;
        int b=50;
        int max=0;
        if(a>b)max=a;
        else max=b;
        System.out.println("max="+max);
    }

}

     输出结果：max=50

public class MaxMoreDemo1 {

    public static void main(String[] args) {
        int[] a= {2,3,4,5,9,7,8};
        int max=0;
        for(int i=0;i<a.length;i++) {
            if(a[i]>max)max=a[i];
        }
        System.out.println("max="+max);
    }

}

public class MaxMoreDemo2 {

    public static void main(String[] args) {
        int[] a= {2,3,4,5,9,7,8};
        int max=0;
        for(int i=0;i<a.length-1;i++) {
            if(a[i]>a[i+1]&&a[i]>max)  max=a[i];
            else if(a[i+1]>a[i]&&a[i+1]>max)  max=a[i+1];
        }
        System.out.println("max="+max);
    }

}

public class MaxMoreDemo {

    public static void main(String[] args) {
        int[] a= {2,3,4,5,9,7,8};
        int max=0;
        for(int i=1;i<a.length;i++) {
            for(int j=i-1;j>=0;j--) {
                if(a[j+1]>a[j]&&a[j+1]>max)  max=a[j+1];
            }
        }
        System.out.println("max="+max);
    }

}

       以上三种方法均可找出最大值，输出结果为：max=9,最小值方法相同

      平均值：

public class Avg {

    public static void main(String[] args) {
        int[] a= {2,3,4,5,9,7,8};
        int sum=0;
        int avg=0;
        for(int i=0;i<a.length;i++) {
            sum+=a[i];
        }
        avg=sum/a.length;
        System.out.println("avg="+avg);
    }
}

    输出结果：avg=5

二、今日遇到的问题

     今日的小学期题目还没有弄懂

三、明日计划

    继续学习第三章数字的排序、查找，继续阅读大道至简