第4次Java作业+LSYang

【1】

 1 public class Java401 {
 2     public static void main(String[] args) {
 3         String str1="Java技术学习班 20070326";
 4         String str2="Java技术学习班 20070326 MLDN 老师";
 5         String str3="330521199601221711";
 6         System.out.println(str1.substring(10,18));
 7         System.out.println(str1.charAt(7));
 8         System.out.println(str1.replaceAll("0", ""));
 9         System.out.println(str2.replaceAll(" ", ""));
10         System.out.println(str3.substring(6,14));
11         String str="MLDN JAVA";
12         String newStr=str.replaceAll("JAVA", "J2EE");
13         System.out.println("替换之后的结果："+newStr);
14     }
15 }

程序运行结果

【2】

 1 class Book{
 2     private String name;
 3     private int id;
 4     private float price;
 5     private static int num=12;
 6     private static int count=0;
 7     public Book(){
 8         count++;
 9         this.id=count;
10     }
11     public Book(int id){
12         this.id=id;
13     }
14     public int getId(){
15         return this.id;
16     }
17     public Book(String name,float price){
18         this.name=name;
19         this.price=price;
20         this.num=num;
21     }
22     public void setName(String name){
23         this.name=name;
24     }
25     public String getName(){
26         return this.name;
27     }
28     public void setPrice(float price){
29         this.price=price;
30     }
31     public float getPrice(){
32         return this.price;
33     }
34     public void setNum(int num){
35         this.num=num;
36     }
37     public int getNum(){
38         return this.num;
39     }
40 }
41 public class Java402 {
42     public static void main(String[] args) {
43         Book book[]=new Book[6];
44         book[0]=new Book("解忧杂货店",36.9f);
45         book[1]=new Book("名侦探的秘密 ",26.6f);
46         book[2]=new Book("白夜行 ",67.9f);
47         book[3]=new Book("流星之绊 ",52.5f);
48         book[4]=new Book("名侦探的守则 ",62.3f);
49         book[5]=new Book("彷徨之刃 ",13f);
50         for(int i=0;i<book.length;i++){
51             System.out.println("编号："+new Book().getId()
52             +"\t 书名："+book[i].getName()
53             +"\t 价格："+book[i].getPrice()
54             +"\t 数量："+book[i].getNum());
55         }
56         System.out.println("图书总量为："+(new Book().getId()-1)*book[1].getNum());
57     }
58 }

程序运行结果