import java.io.*;

abstract class DbObject {
    java.util.Scanner kb = new java.util.Scanner(System.in);
    public void writeString(String s, RandomAccessFile out) throws IOException {
        for (int i = 0; i < s.length(); i++)
            out.writeChar(s.charAt(i));
    }
    public String readString(int len, RandomAccessFile in) throws IOException {
        StringBuffer s = new StringBuffer(len);
        for (int i = 0; i < len; i++)
            s.append(in.readChar());
        return s.toString();
    }
    abstract public void writeToFile(RandomAccessFile out) throws IOException;
    abstract public void readFromFile(RandomAccessFile in) throws IOException;
    abstract public void readFromConsole();
    abstract public void writeLegibly();
    abstract public void readKey();
    abstract public void copy(DbObject[] db);
    abstract public int size();
}