import java.io.*;

public class main {

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

    String code = loadTextFile("input/main.java", null);

    if (code == null)

      throw new RuntimeException("Nothing to do (no input/main.java)");

    String modified = modifyCode(code);

    saveTextFile("output/main.java", modified);

    System.out.println("output/main.java saved!");

  }

  public static String modifyCode(String code) {

    return code.replaceAll("System.out.println\\(", "if (false) System.out.println(");

  }

  /** writes safely (to temp file, then rename) */

  public static void saveTextFile(String fileName, String contents) throws IOException {

    File file = new File(fileName);

    File parentFile = file.getParentFile();

    if (parentFile != null)

      parentFile.mkdirs();

    String tempFileName = fileName + "_temp";

    FileOutputStream fileOutputStream = new FileOutputStream(tempFileName);

    OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream, "UTF-8");

    PrintWriter printWriter = new PrintWriter(outputStreamWriter);

    printWriter.print(contents);

    printWriter.close();

    if (file.exists() && !file.delete())

      throw new IOException("Can't delete " + fileName);

    if (!new File(tempFileName).renameTo(file))

      throw new IOException("Can't rename " + tempFileName + " to " + fileName);

  }

  public static String loadTextFile(String fileName, String defaultContents) throws IOException {

    if (!new File(fileName).exists())

      return defaultContents;

    FileInputStream fileInputStream = new FileInputStream(fileName);

    InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "UTF-8");

    return loadTextFile(inputStreamReader);

  }

  public static String loadTextFile(Reader reader) throws IOException {

    StringBuilder builder = new StringBuilder();

    try {

      BufferedReader bufferedReader = new BufferedReader(reader);

      String line;

      while ((line = bufferedReader.readLine()) != null)

        builder.append(line).append('\n');

    } finally {

      reader.close();

    }

    return builder.length() == 0 ? "" : builder.substring(0, builder.length()-1);

  }

}