SUMMARY The efficiency of object-oriented programs has become a point of great interest. One necessary factor for program efficiency is the optimization techniques involved. This paper presents the performance of several variations of a given Ctt program and compares them with a version that uses no object- oriented features. Our result indicates that some object-oriented features in Ctt are not well optim- ized in current Ctt compilers. We thus discuss some code optimization techniques that can improve the efficiency based on the given Ctt program. The Ci-t language' is one of the most efficient object-oriented programming languages. A recent comparison2 using a simple 'database' program showed that the Ctt version is faster than those in the other four modem languages: Oberon-2, Modula-3, Sather, and Self. The designers of Ci-t have carefully considered the efficiency issue. For example, dynamic dispatch is not by default for the invocation of a member function in Ctt. In addition, C++ is strongly typed: it is easier to provide efficient (constant time) dynamic dispatch when the type information is available. The C3 programs are thought to be efficient and compact. Do Ctt programs inherit this property? Can we write Ctt programs without concern for the underlying implementation of object-ori- ented constructs, even when the efficiency of programs is concerned? Answering the above questions depends on the applications and compiler techno- logies of Ci-t. It may be very difficult. This paper presents a case study to show several efficiency and optimization problems specific to Ctt. It measures the efficiency of some variations of a given Ctt example program (quick sort) and compares them with a version using no object-oriented features. These variations include a class without inheritance, a class whose base class is empty, and a class whose base class is abstract. The experiment uses four compilers on PC and workstation platforms. Our results indi- cate that many current C-H compilers still do not produce well optimized codes for