新手的提问。。。

[qq8574157]

import java.io.*;
class Student
{
private int num;
private String name;
private double score;
public void setImfo() throws Exception
{
InputStreamReader isr= new InputStreamReader(System.in);
BufferedReader br= new BufferedReader(isr);
System.out.print("num:");
num=Integer.parseInt(br.readLine());
System.out.print("name:");
name=br.readLine();
System.out.print("score:");
score=Double.parseDouble(br.readLine());
}
public double reScore()
{
return score;
}
}
public class Test
{
public static void main(String [] args) throws Exception
{
Student [] stu= new Student [5];
double aver=0;
for(int i=0;i<stu.length;++i)
{
stu[i].setImfo(); //Exception in thread "main" java.lang.NullPointerException------此处为什么会出现这个错误？原因以及解决的方法？？
aver+=stu[i].reScore();
}
System.out.println("aver= "+aver/stu.length);
}
}

[chen09]

Student [] stu= new Student [5];
只是stu初始化了，stu[0-4]还都是null，你没有初始化数组的元素呀。
加一句 stu[i]= new Student();

[qq8574157]

嗯 明白了 谢谢了哦。。。