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

 1 public class CardDemo {
 2 
 3     public static void main(String[] args) {
 4         String[] suit= {"梅花","方块","红桃","黑桃"};
 5         String[] number= {"A","2","3","4","5","6","7","8","9","10","J","Q","k"};
 6         String[] cards=new String[64];
 7         for(int i=0;i<cards.length-2;i++) {
 8             cards[i]=suit[i%suit.length]+number[i%number.length];
 9         }
10         cards[cards.length-2]="大王";
11         cards[cards.length-1]="小王";
12         for(int i=0;i<cards.length;i++) {
13             System.out.print(cards[i]+"	");
14             if(i%13==0&&i!=0)System.out.println();
15         }
16     }
17 
18 }

（2）ATM机取钱

 1 import java.util.Scanner;
 2 public class ATM {
 3     public static void main(String[] args) {
 4         System.out.print("请输入密码：");
 5         Scanner con=new Scanner(System.in);
 6         String line=con.nextLine();
 7         if(line.equals("1234")) {
 8             System.out.println("1、取款");
 9             System.out.println("2、退出");
10             int num=con.nextInt();
11             switch(num) {
12             case 1:
13                 System.out.println("1、取款100");
14                 System.out.println("2、取款200");
15                 System.out.println("3、取款500");
16                 System.out.println("4、其他");
17                 int money=con.nextInt();
18                 switch(money) {
19                 case 1:
20                     System.out.println("取款100！");
21                     break;
22                 case 2:
23                     System.out.println("取款200！");
24                     break;
25                 case 3:
26                     System.out.println("取款500！");
27                     break;
28                 case 4:
29                     System.out.println("请输入取款金额:");
30                     int other=con.nextInt();
31                     System.out.println("取款"+other+"元！");
32                     break;
33                 }
34                 break;
35             case 2:
36                 System.out.println("欢迎下次光临！谢谢！");
37                 break;
38                 
39             }
40         }
41 
42     }
43 
44 }

2、学习了第三章的内容值的比较

（1）值得比较

最大值：

 1 public class MaxDemo {
 2     public static void main(String[] args) {
 3         int a=30;
 4         int b=50;
 5         int max=0;
 6         if(a>b)max=a;
 7         else max=b;
 8         System.out.println("max="+max);
 9     }
10 
11 }

输出结果：max=50

 1 public class MaxMoreDemo1 {
 2 
 3     public static void main(String[] args) {
 4         int[] a= {2,3,4,5,9,7,8};
 5         int max=0;
 6         for(int i=0;i<a.length;i++) {
 7             if(a[i]>max)max=a[i];
 8         }
 9         System.out.println("max="+max);
10     }
11 
12 }

 1 public class MaxMoreDemo2 {
 2 
 3     public static void main(String[] args) {
 4         int[] a= {2,3,4,5,9,7,8};
 5         int max=0;
 6         for(int i=0;i<a.length-1;i++) {
 7             if(a[i]>a[i+1]&&a[i]>max)  max=a[i];
 8             else if(a[i+1]>a[i]&&a[i+1]>max)  max=a[i+1];
 9         }
10         System.out.println("max="+max);
11     }
12 
13 }

 1 public class MaxMoreDemo {
 2 
 3     public static void main(String[] args) {
 4         int[] a= {2,3,4,5,9,7,8};
 5         int max=0;
 6         for(int i=1;i<a.length;i++) {
 7             for(int j=i-1;j>=0;j--) {
 8                 if(a[j+1]>a[j]&&a[j+1]>max)  max=a[j+1];
 9             }
10         }
11         System.out.println("max="+max);
12     }
13 
14 }

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：

 1 public class Avg {
 2 
 3     public static void main(String[] args) {
 4         int[] a= {2,3,4,5,9,7,8};
 5         int sum=0;
 6         int avg=0;
 7         for(int i=0;i<a.length;i++) {
 8             sum+=a[i];
 9         }
10         avg=sum/a.length;
11         System.out.println("avg="+avg);
12     }
13 }

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