System.in.read()不读 [英] System.in.read() does not read
问题描述
我是Java的新手,所以如果这是一个非常小的错误,请原谅我,
这是我的代码:
I am new to Java, so please forgive me if it is a very small mistake,
here's my code:
import java.io.*;
public class election
{
public static void main(String args[])
{
boolean x=false;
Ballot ballot=new Ballot();
int n;
while(x!=true)
{
System.out.println("Cast your vote to(1-5): ");
try
{
n=System.in.read();
System.out.flush();
ballot.add(n);
System.out.println("Enter 0 to exit, enter 1 to vote again: ");
n = System.in.read();
if(n==0)
{
x=true;
}
else
{
x=false;
}
}
catch(IOException e)
{
System.out.println("I/O Error");
System.exit(1);
}
}
}
}
class Ballot
{
int votes,spoilt;
int cand[] = new int[5];
//methods
void add(int n)
{
votes=votes+1;
if(n <= 5 && n>=1)
{
cand[n-1]=cand[n-1]+1;
}
else
{
spoilt = spoilt + 1;
}
}
void display()
{
System.out.println("Total votes cast: " + votes);
for(int i=0;i<5;i++)
{
System.out.println("Candidate " + (i+1) + ": " + cand[i]);
}
System.out.println("Spoilt: " + spoilt);
System.out.println("Valid votes: " + (votes-spoilt));
}
Ballot()
{
votes=0;
spoilt=0;
for(int i=0;i<5;i++)
{
cand[i]=0;
}
}
}
我在编译后运行它,第18行(n = System.in.read())被跳过。
我得到的输出是:
when i run it after compiling, the 18th line(n = System.in.read()) gets skipped.
The output I get is this:
投票给(1-5):
1
输入0退出,输入1再次投票:
投票到(1-5):
2
输入0退出,输入1再次投票:
投票给(1-5):
^ C
Cast your vote to(1-5):
1 Enter 0 to exit, enter 1 to vote again:
Cast your vote to(1-5):
2 Enter 0 to exit, enter 1 to vote again:
Cast your vote to(1-5):
^C
n
的值不是 read()
这使程序成为无限循环。
The value of n
is not read()
which makes the program an infinite loop.
感谢您的帮助。
推荐答案
我认为它如果您使用Scanner类会更容易。您可以实例化扫描程序对象,如扫描程序扫描=新扫描程序(System.in);
。然后第18行可以变成 n = scan.nextInt();
这应该正确读取用户输入。有关Scanner类的更多信息,请参阅Java文档: http://docs.oracle.com/javase/6/docs/api/java/util/Scanner.html 。希望这会有所帮助。
I think it would be easier if you made use of the Scanner class. You can instantiate a scanner object like so Scanner scan = new Scanner(System.in);
. Then line 18 can become n = scan.nextInt();
This should properly read the user input. For more information on the Scanner class see the Java docs: http://docs.oracle.com/javase/6/docs/api/java/util/Scanner.html. Hope this helped.
这篇关于System.in.read()不读的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!