如何在Java中读取多行输入 [英] How to read input with multiple lines in Java

问题描述

我们的教授正在使我们使用Java进行一些基本编程，他提供了一个网站以及一切用于注册和提交我们的问题的方法，今天我需要做一个例子，我觉得自己步入正轨，但我只是无法弄清楚其余的.这是实际的问题:

Our professor is making us do some basic programming with Java, he gave a website and everything to register and submit our questions, for today I need to do this one example I feel like I'm on the right track but I just can't figure out the rest. Here is the actual question:

**Sample Input:**
10 12
10 14
100 200

**Sample Output:**
2
4
100

这是到目前为止我得到的:

And here is what I've got so far :

public class Practice {

    public static int calculateAnswer(String a, String b) {
        return (Integer.parseInt(b) - Integer.parseInt(a));
    }

    public static void main(String[] args) {
        System.out.println(calculateAnswer(args[0], args[1]));
    }
}

现在我总是得到答案2，因为我正在阅读单行，如何考虑所有行?谢谢

Now I always get the answer 2 because I'm reading the single line, how can I take all lines into account? thank you

由于某些奇怪的原因，每次我要执行时都会收到此错误:

For some strange reason every time I want to execute I get this error:

C:\sonic>java Practice.class 10 12
Exception in thread "main" java.lang.NoClassDefFoundError: Fact
Caused by: java.lang.ClassNotFoundException: Fact.class
        at java.net.URLClassLoader$1.run(URLClassLoader.java:20
        at java.security.AccessController.doPrivileged(Native M
        at java.net.URLClassLoader.findClass(URLClassLoader.jav
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248
Could not find the main class: Practice.class.  Program will exit.

无论使用什么版本的答案，我都会收到此错误，该怎么办?

Whatever version of answer I use I get this error, what do I do ?

但是，如果我在eclipse中运行它，则运行方式>运行配置->程序参数

However if I run it in eclipse Run as > Run Configuration -> Program arguments

10 12
10 14
100 200

我没有输出

编辑

我已经取得了一些进展，起初我遇到了编译错误，然后是运行时错误，现在我得到了错误的答案，所以任何人都可以帮我解决一下这是怎么回事:

I have made some progress, at first I was getting the compilation error, then runtime error and now I get wrong answer, so can anybody help me what is wrong with this:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;

public class Practice {

    public static BigInteger calculateAnswer(String a, String b) {
        BigInteger ab = new BigInteger(a);
        BigInteger bc = new BigInteger(b);
        return bc.subtract(ab);
    }

    public static void main(String[] args) throws IOException {
        BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in)); 
        String line; 

        while ((line = stdin.readLine()) != null && line.length()!= 0) { 
            String[] input = line.split(" "); 
            if (input.length == 2) { 
                System.out.println(calculateAnswer(input[0], input[1])); 
            } 
        } 
    }
}

推荐答案

我终于得到了它，无论出于何种原因都被提交了13次，第14位法官"接受了我的回答，这里是:

I finally got it, submited it 13 times rejected for whatever reasons, 14th "the judge" accepted my answer, here it is :

import java.io.BufferedInputStream;
import java.util.Scanner;

public class HashmatWarrior {

    public static void main(String args[]) {
        Scanner stdin = new Scanner(new BufferedInputStream(System.in));
        while (stdin.hasNext()) {
            System.out.println(Math.abs(stdin.nextLong() - stdin.nextLong()));
        }
    }
}

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