aktuelle.kurse/old_m411/docs/Daten-Uebungen-CodeBeispiele/InputReader.java

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2021-08-06 18:08:13 +02:00
import java.io.BufferedInputStream;
import java.util.InputMismatchException;
import java.util.Locale;
import java.util.Scanner;
import java.util.regex.Pattern;
/**
* InputReader.
* Uses stuff from Sedgewick's standard classes.
*
* @author Julian
*
*/
public class InputReader {
private Scanner scanner;
// assume Unicode UTF-8 encoding
private static final String CHARSET_NAME = "UTF-8";
// assume language = English for consistency with System.out.
private static final Locale LOCALE = Locale.ENGLISH;
// the default token separator; we maintain the invariant that this value
// is held by the scanner's delimiter between calls
private static final Pattern WHITESPACE_PATTERN
= Pattern.compile("\\p{javaWhitespace}+");
// used to read the entire input. source:
// http://weblogs.java.net/blog/pat/archive/2004/10/stupid_scanner_1.html
private static final Pattern EVERYTHING_PATTERN
= Pattern.compile("\\A");
/**
* Constructor which also instantiates the Scanner and sets character-set and
* locale.
*/
public InputReader(){
scanner = new Scanner(new BufferedInputStream(System.in), CHARSET_NAME);
scanner.useLocale(LOCALE);
}
/**
* Read and return the next string.
*/
public String readString() {
return scanner.next();
}
/**
* Read and return the next int.
*/
public int readInt() {
return scanner.nextInt();
}
/**
* Read and return the next boolean, allowing case-insensitive
* "true" or "1" for true, and "false" or "0" for false.
*/
public boolean readBoolean() {
String s = readString();
if (s.equalsIgnoreCase("true")) return true;
if (s.equalsIgnoreCase("false")) return false;
if (s.equals("1")) return true;
if (s.equals("0")) return false;
throw new InputMismatchException();
}
/**
* Read and return the remainder of the input as a string.
*/
public String readAll() {
if (!scanner.hasNextLine())
return "";
String result = scanner.useDelimiter(EVERYTHING_PATTERN).next();
// not that important to reset delimeter, since now scanner is empty
scanner.useDelimiter(WHITESPACE_PATTERN); // but let's do it anyway
return result;
}
/**
* Read all strings until the end of input is reached, and return them.
*/
public String[] readAllStrings() {
// we could use readAll.trim().split(), but that's not consistent
// since trim() uses characters 0x00..0x20 as whitespace
String[] tokens = WHITESPACE_PATTERN.split(readAll());
if (tokens.length == 0 || tokens[0].length() > 0)
return tokens;
String[] decapitokens = new String[tokens.length-1];
for (int i = 0; i < tokens.length-1; i++)
decapitokens[i] = tokens[i+1];
return decapitokens;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
}
}