private Statement stmt() {
        Statement stmt;
        assert theTokenizer.ttype == StreamTokenizer.TT_WORD;

        String word = theTokenizer.sval;
        if(word.equals("output")) {
            stmt = outputStmt();
        } else if(word.equals("if")) {
            stmt = ifStmt();
        } else if(word.equals("while")) {
            stmt = whileStmt();
        } else {
            stmt = assignStmt(word);
        }

        return stmt;
    }