8.18

8.19

学完基础，写了学生系统。
import java.io.*;
public class Student {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("hello world!");
Stu stu=new Stu();
System.out.println("1.学号查成绩");
System.out.println("2.成绩查学号");
System.out.println("3.统计");
System.out.println("4.删除成绩");
InputStreamReader isr=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(isr);
try{
int input=Integer.parseInt(br.readLine());
switch(input)
{
case 1:
System.out.println("请输入所要查询成绩的学号：");
int a1=Integer.parseInt(br.readLine());
stu.SearchScore(a1);
break;
case 2:
System.out.println("请输入所要查询学号的成绩：");
float a2=Float.parseFloat(br.readLine());
stu.SearchNum(a2);
break;
case 3:
stu.Statistics();
break;
case 4:
System.out.println("请输入所要删除成绩的学号：");
int a3=Integer.parseInt(br.readLine());
stu.SearchScore(a3);
default:
System.out.println("输入错误!");
break;
}
}catch(Exception e){
e.printStackTrace();
}finally{
try{
br.close();
}catch(IOException e){
e.printStackTrace();
}
}
}
}
class Stu{
float score[]=null;
int size=10;
public Stu() //构造函数
{
score=new float[size];
InputStreamReader isr=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(isr);
try{
for(int i=0;i<score.length;i++)
{
System.out.println("请输入第"+(i+1)+"学生成绩");
score[i]=Float.parseFloat(br.readLine());
}
}catch(Exception e){
e.printStackTrace();
}
}
//学号查成绩
public void SearchScore(int a){
System.out.println("学号"+a+"的成绩是："+score[a]);
}
//成绩查学号
public void SearchNum(float a){
for(int i=0;i<score.length;i++)
{
if(a==score[i])
System.out.println("成绩"+a+"的学号是："+i);
}
}
//统计
public void Statistics(){
int fail=0;
int bad=0;
int soso=0;
int good=0;
int nice=0;
try{
for(int i=0;i<score.length;i++)
{
int SC=0;
SC=(int)score[i]/10;
switch(SC)
{
case 0:
case 1:
case 2:
case 3:
case 4:
case 5:
fail++;
break;
case 6:
bad++;
break;
case 7:
soso++;
break;
case 8:
good++;
break;
case 9:
nice++;
break;
default:
System.out.println("输入错误");
break;
}
}
}catch(Exception e){
e.printStackTrace();
}
}
//删除功能
public void Delete(int a){
score[a]=0;
}
}