您所在位置：主题：为什么出现错误：java.lang.NullPointerException
iamanewer
[专家分：30] 发布于 2008-04-13 22:15:00
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
public class Exercise4_2 {
/**
* @param args
*/
private static int[] a;
public static void main(String[] args) {
// TODO Auto-generated method stub
if(args.length!=1){
System.out.println("Usage: java Exercise4_2 filename");
System.exit(1);
}
try{
BufferedReader in=new BufferedReader(new FileReader(args[0]));
String line;
int i=0;
int sum=0;
while((line=in.readLine())!=null){
a[i++]=Integer.parseInt(line);
}
for(int j=0;j<a.length;j++){
sum+=a[i];
}
System.out.println("The average number is "+sum/a.length);
System.out.println("The total number is"+a.length);
}catch(IOException e){
e.printStackTrace();
}
}
}
import java.io.FileReader;
import java.io.IOException;
public class Exercise4_2 {
/**
* @param args
*/
private static int[] a;
public static void main(String[] args) {
// TODO Auto-generated method stub
if(args.length!=1){
System.out.println("Usage: java Exercise4_2 filename");
System.exit(1);
}
try{
BufferedReader in=new BufferedReader(new FileReader(args[0]));
String line;
int i=0;
int sum=0;
while((line=in.readLine())!=null){
a[i++]=Integer.parseInt(line);
}
for(int j=0;j<a.length;j++){
sum+=a[i];
}
System.out.println("The average number is "+sum/a.length);
System.out.println("The total number is"+a.length);
}catch(IOException e){
e.printStackTrace();
}
}
}
