黑马程序员 IO和集合的小练习

来源：互联网发布：2013网络歌曲排行榜编辑：程序博客网时间：2024/04/30 04:48

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需求：五个学生，每个学生有三门成绩，从键盘录入以上数据包括（姓名，三门课的成绩）

如：zhangsan ，30,40,50 计算总成绩，并把信息和计算的结果的高低顺序写入硬盘的“stu.ext”。

分析：1，建立学生对象。

2，建立一个类，可以操作学生。里面要建立集合。

import java.io.*;import java.util.*;class  StudentTest{public static void main(String[] args) {StudentTool.get();}}class StudentTool{public static void  get(){BufferedReader bfr = null;BufferedWriter bfw = null;TreeSet<Student> ts = new TreeSet<Student>();try{bfr = new BufferedReader(new InputStreamReader(System.in));bfw = new BufferedWriter(new FileWriter("stud.txt"));String st = null;while ((st = bfr.readLine()) != null){if("over".equals(st))break;String[] sz = st.split(",");Student stu = new Student(sz[0],Integer.parseInt(sz[1]),Integer.parseInt(sz[2]),Integer.parseInt(sz[3]));ts.add(stu);}for(Student info : ts){bfw.write(info.toString()+  "-----");bfw.write(info.getSum()+ "");bfw.newLine();bfw.flush();}}catch (IOException e){throw new RuntimeException("cuo");}finally{try{if(bfr != null)bfr.close();}catch (IOException e ){throw new RuntimeException("cuol");}try{if(bfw != null)bfw.close();}catch (IOException e ){throw new RuntimeException("cuo2");}}}}class Student implements Comparable<Student>{private String name;private int ms,yw,eg;private int sum;Student(String name, int ms, int yw, int eg){this.name = name;this.ms = ms;this.yw = yw;this.eg = eg;sum = ms + yw + eg;}public String getName(){return name;}public int getSum(){return sum;}public int compareTo( Student s){int num = (new Integer(s.sum)).compareTo(new Integer(this.sum));if(num == 0)num = s.name.compareTo(this.name);return num;}public int hashCode(){return name.hashCode() + sum * 7;}public boolean equals(Object obj){if(!(obj instanceof Student))throw new RuntimeException("类型不匹配");Student st = (Student)obj;return this.name.equals(st.name) && this.sum ==st.sum;}public String toString(){return  "["+name + "]" + "[" + ms +"]" +"["+ yw + "]" + "["+ eg + "]";}}

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