在SPOJ上，如何在Java中的EOF之前读取此程序的输入? [英] How do I read input until EOF in Java for this program on SPOJ?

问题描述

问题网址: http://www.spoj.com/problems/PT07H/

顺便说一句，我试图通过3种不同的方法读取输入，但是没有成功，控制永远不会退出while()循环(即，它永远不会检测到EOF或EOS).

By the way, I tried to read an input by 3 different methods but no success, control never come out of while() loop (i.e., It never detects EOF or EOS).

这是我的代码，该代码读取输入的XML:

Here's my code that reads an input XML:

public static void main(String[] args) throws Exception {

        // Input & Output
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        OutputStream out = new BufferedOutputStream(System.out);

        int data;
        char c;
        String line;
        StringBuilder xml = new StringBuilder();

        // Read input
/*
        // Method-1
        Scanner in = new Scanner(System.in);
        while (in.hasNextLine()) {
            line = in.nextLine();
            for (int i = 0; i < line.length(); i++) {
                c = line.charAt(i);
                if (isValid(c)) {
                    xml.append(c);
                }
            }
        }
        // Method-2
        while ((data = br.read()) != -1) {
            c = (char) data;
            if (isValid(c)) {
                xml.append(c);
            }
        }
*/
        // Method-3
        while ((line = br.readLine()) != null) {
            for (int i = 0; i < line.length(); i++) {
                c = line.charAt(i);
                if (isValid(c)) {
                    xml.append(c);
                }
            }
        }

}

推荐答案

标准输入实际上 没有EOF，因此您将永远看不到它.当您从确实有结尾的实际文件(或其他流)中读取内容时，您的方法#3将起作用.

Standard input actually has no EOF, so you'll never see it. Your method #3 will work when reading from an actual file (or other stream) which does have an end.

(不确定，您可能想尝试在标准输入(Ctrl-D或Ctrl-Z)上键入" EOF，这可能行不通，不确定.)

(You may want to try to 'type' an EOF on the stdin (Ctrl-D or Ctrl-Z), which may or may not work, not sure.)

另请参见此问题.

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