初学者问题,请指教
import java.io.*;
public class Class1
{
public static void main (String[] args)
{
try
{
char a='y';
while(a!='n'||a!='N')
{
float num[]=new float[3];
int i;
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.print("请输入三门课程的成绩:");
for(i=0;i<num.length;i++)
num[i]=Float.valueOf(br.readLine()).floatValue();
float ave;
ave=(num[0]+num[1]+num[2])/3;
System.out.println("平均成绩:"+ave);
System.out.print("退出否?");
a=(char)System.in.read();
}
}
catch(IOException e){System.err.println(e.toString());}
}
}
运行第一次循环时显示An exception of type'java.lang.NumberFormatException'was not handled