本帖最后由 likairoudou 于 2013-7-12 22:21 编辑
- /*
- 有五个学生,每个学生有3门课的成绩,
- 从键盘输入以上数据(包括姓名,三门课成绩),
- 输入的格式:如:zhagnsan,男,30,40,60计算出总成绩,平均成绩
- 并把学生的信息和计算出的总分数高低顺序存放在磁盘文件"stud.txt"中。
- 1,描述学生对象。
- 2,定义一个可操作学生对象的工具类。
- 思想:
- 1,通过获取键盘录入一行数据,并将该行中的信息取出封装成学生对象。
- 2,因为学生有很多,那么就需要存储,使用到集合。因为要对学生的总分排序。
- 所以可以使用TreeSet。
- 3,将集合的信息写入到一个文件中。
- */
- import java.io.*;
- import java.util.*;
- class Student implements Comparable<Student>
- { private double xh;
- private String name;
- private String sex;
- private double ja,cc,php;
- private double sum,ave;
- Student(double xh,String name,String sex,double ja,double cc,double php)
- { this.xh=xh;
- this.name = name;
- this.sex=sex;
- this.ja = ja;
- this.cc = cc;
- this.php = php;
- sum = ja + cc+ php;
- ave = sum/3;
- }
- public double compareTo(Student s)
- {
- double num = new Double(this.sum).compareTo(new Double(s.sum));
- if(num==0)
- return this.name.compareTo(s.name);
- return num;
- }
- public double getXh()
- {
- return xh;
- }
- public String getName()
- {
- return name;
- }
- public String getSex()
- {
- return sex;
- }
- public double getSum()
- {
- return sum;
- }
- public double getAve()
- {
- return ave;
- }
- public boolean equals(Object obj)
- {
- if(!(obj instanceof Student))
- throw new ClassCastException("类型不匹配");
- Student s = (Student)obj;
- return this.name.equals(s.name) && this.sum==s.sum;
- }
- public String toString()
- {
- return "["+xh+" "+name+" "+sex+" "+ja+" "+cc+" "+php+"]";
- }
- }
- class StudentInfoTool //工具类方法
- {
- public static Set<Student> getStudents()throws IOException
- {
- return getStudents(null);
- }
- public static Set<Student> getStudents(Comparator<Student> cmp)throws IOException
- {
- BufferedReader bufr =
- new BufferedReader(new InputStreamReader(System.in));
- String line = null;
- Set<Student> stus = null;
- if(cmp==null)
- stus = new TreeSet<Student>();
- else
- stus = new TreeSet<Student>(cmp);
- while((line=bufr.readLine())!=null)
- {
- if("over".equals(line))
- break;
- String[] info = line.split(" ");
- Student stu = new Student(Double.parseDouble(info[0]),
- info[1],
- info[2],
- Double.parseDouble(info[3]),
- Double.parseDouble(info[4]),
- Double.parseDouble(info[5]));
- stus.add(stu);
- }
- bufr.close();
- return stus;
- }
- public static void write2File(Set<Student> stus)throws IOException
- {
- BufferedWriter bufw = new BufferedWriter(new FileWriter("stuinfo.txt"));
- for(Student stu : stus)
- {
- bufw.write(stu.toString()+"\t");
- bufw.write(stu.getSum()+"\t");
- bufw.write(stu.getAve()+"");
- bufw.newLine();
- bufw.flush();
- }
- bufw.close();
- }
- }
- class StudentInfoTest
- {
- public static void main(String[] args) throws IOException
- {
- Comparator<Student> cmp = Collections.reverseOrder();
- Set<Student> stus = StudentInfoTool.getStudents(cmp);
- StudentInfoTool.write2File(stus);
- }
- }
复制代码 原来是int类型的。。我就改成double类型的。。然后就挂了。请问 怎么修改
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