为什么KeyboardInput()会报错?

[hbliuren0]

//编写一个程序，输入10个整数计算并显示它们的和，平均值
public class Program2{
public static void main(final String[] args){
KeyboardInput input=new KeyboardInput();
System.out.println("Please enter ten integers:");
int i=1,sum=0;
double sql=0;
while(i<=10){
System.out.println("Please enter integer:");
int a=input.readInteger();
sum=sum+a;
i=i+1;
}
sql=sum/10;
System.out.println("The sum is " + sum);
System.out.println("The sql is " + sql);
}
}

[skylan]

KeyboardInput 类你写了吗？这个类是要自己写的，不然就不会成功运行

[hbliuren0]

KeyboardInput的类不能在类库中调用吗?怎么写呀?

[skylan]

import java.io.*;
public class KeyboardInput {
private final BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
public final synchronized int readInteger(){
String input="";
int value=0;
try{
input=in.readLine();
}catch(IOException e){}
if(input!=null){
try{
value=Integer.parseInt(input);
}catch(NumberFormatException e){}
}
return value;
}
public final synchronized long readLong(){
String input="";
long value=0L;
try{
input=in.readLine();
}catch(IOException e){}
if (input!=null){
try{
value=Long.parseLong(input);
}catch(NumberFormatException e){}
}
return value;
}
public final synchronized double readDouble(){
String input="";
double value=0.0D;
try{
input=in.readLine();
}catch(IOException e){}
if(input!=null){
try{
value=Double.parseDouble(input);
}catch(NumberFormatException e){}
}
return value;
}
public final synchronized float readFloat(){
String input="";
float value=0.0F;
try{
input=in.readLine();
}catch(IOException e){}
if(input!=null){
try{
value=Float.parseFloat(input);
}catch(NumberFormatException e){}
}
return value;
}
public final synchronized char readCharacter(){
char c=' ';
try{
c=(char)in.read();
}catch(IOException e){}
return c;
}
public final synchronized String readString(){
String s="";
try{
s=in.readLine();
}catch(IOException e){}
if(s==null){
s="";
}
return s;
}
}
你在试试看能不能运行。

[skylan]

如果还报错误，你就把public final synchronized int readInteger()；
public final synchronized long readLong()；
public final synchronized double readDouble()；
public final synchronized float readFloat()；
public final synchronized char readCharacter()；
public final synchronized String readString()；
里面的final 去掉，就ok了。因为声明为final 的函数只能在本类中调用。

[zhigangsun]

嗯，支持楼上的。