高分求解决一个java问题！我就剩下40分了，都给了，呵呵。

[wangming7306]

import java.io.IOException;

class TestWhile{
public static void main(String[] args) throws IOException{
char response;
System.out.println("Are you felling better about " +
"programming?(Y or N)");
System.out.flush();
response=(char)System.in.read();
while ( response !='Y'&& response != 'N' ){
System.out.println("Invalid letter.");
System.out.println("Enter only 'Y' or 'N'");
response=(char)System.in.read();
//System.out.println("a" + response + "b");
}

if(response =='Y')
System.out.println("I am grad.");
else
System.out.println("Keep trying!");
}
}
/*
但运行结果却是这样:
Are you felling better about programming?(Y or N)
d
Invalid letter.
Enter only 'Y' or 'N'
Invalid letter.
Enter only 'Y' or 'N'
Invalid letter.
Enter only 'Y' or 'N'
Y
I am grad.

为什么在输入d时,循环了了三次呢,，请说明原因及提出修改方法
*/

[huoyin]

修改后的代码：

import java.io.*;

class TestWhile{
public static void main(String[] args) throws IOException{
String response;
System.out.println("Are you felling better about " +
"programming?(Y or N)");
System.out.flush();
BufferedReader in = new BufferedReader( new InputStreamReader(System.in));
response=in.readLine();
while ( !response.equals("Y") && !response.equals("N") ){
System.out.println("Invalid letter.");
System.out.println("Enter only 'Y' or 'N'");
response=in.readLine();
//System.out.println("a" + response + "b");
}

if(response.equals("Y"))
System.out.println("I am grad.");
else
System.out.println("Keep trying!");
}
}

[zqrqq]

因为，你输入d之后回车，真实的输入是d\r\n,一共3个字符，呵呵

[zqrqq]

用readLine会比较保险

[jefyjiang]

正解

[jefyjiang]

lz这里while ( response !='Y'&& response != 'N' )不能那样写,会出现短路

[wangming7306]

完了，我以后没分在发帖子了，嘿嘿

[恭常章]

因为你在控制台输入字符'd'后，按回车键，系统默认在后面追加了\r\n,所以一共是三个字符，循环了三次。
程序作如下修改可解决问题：

import java.io.IOException;

class TestWhile{
public static void main(String[] args) throws IOException{
char response;
System.out.println("Are you felling better about " +
"programming?(Y or N)");
System.out.flush();
response=(char)System.in.read();
while ( response !='Y'&& response != 'N' ){
if(response=='\r' || response=='\n'){
break;
}
System.out.println("Invalid letter.");
System.out.println("Enter only 'Y' or 'N'");
response=(char)System.in.read();
//System.out.println("a" + response + "b");
}

if(response =='Y')
System.out.println("I am grad.");
else
System.out.println("Keep trying!");
}
}

[joejoe1991]

你输入的一个字符再加上回车 一共是三个字符 回车占两个 所以循环了三次。 用BufferedReader比较保险点

[javaflash9]

我也来一个,无限循环(Y,N选到害怕)哈哈!
class TestWhile{
public static void main(String[] args)
throws java.io.IOException{
char response;
do
{
System.out.println("Are you felling better about " + "programming?(Y or N)");

do
{
response=(char)System.in.read();
}while (response=='\r'|response=='\n');

if(response =='Y') System.out.println("I am grad.");
else if(response=='N') System.out.println("Keep trying!");
else
{
System.out.println("Invalid letter.");
System.out.println("Enter only 'Y' or 'N'");
}

}while(response!='Y'|response!='N');
}
}

[rainv]

好像是每天回一次贴可以加10分。
lz不要只会索取，没有奉献哦。