import java.io.Reader;

/** Translating Reader: a stream that is a translation of an
 *  existing reader. */
public class TrReader extends Reader {
    /** A new TrReader that produces the stream of characters produced
     *  by STR, converting all characters that occur in FROM to the
     *  corresponding characters in TO.  That is, change occurrences of
     *  FROM.charAt(0) to TO.charAt(0), etc., leaving other characters
     *  unchanged.  FROM and TO must have the same length. */
    public TrReader(Reader str, String from, String to) {
        // FILL IN
    }

    // FILL IN
    // NOTE: Until you fill in the right methods, the compiler will
    //       reject this file, saying that you must declare TrReader
    //     abstract.  Don't do that; define the right methods instead!
}