@Override
    public void codeGen(Writer w, String indent) throws IOException {
        w.write(indent+"if(");
        cond.codeGen(w, indent);
        w.write(")\n");
        a.codeGen(w, a instanceof Block?indent : indent + "\t");
//        w.write(indent + "\n");
        if (b != null) {
            w.write(indent + "else \n");
            b.codeGen(w, b instanceof IfStatement || b instanceof Block?indent : indent + "\t");
        }
    }