Frederick A. Hosch

Java as a first language: an evaluation

In this note, we outline some issues raised in considering the use of the programming language JavaTM to support a first course in software development. The course - essentially CS 1 - is centered on the design and implementation of simple objects, and employs an iterative specify/design/implement/test strategy to introduce data design and traditional procedural concepts. We enumerate some aspects of the Java language that attracted our interest, and identify some areas of the language design that could be modified to better meet our needs in an introductory computer science course.

Generic instantiations as closures

Higher-order functions are an essential component of a popular programming paradig m called functional programming. In this paper we examine Adas generic facility in terms o f higher-order functions . We do not suggest that a functional style is particularly appropriate fo r Ada, nor do we intend to imply that the semantics of Adas generic units are identical to semantic s that might be given for higher-order functions . Nevertheless some insight into the use of generi c units can be gained by comparing this facility with the definition and use of higher order functions, and questions concerning the behavior of Ada generic units can sometimes be satisfactoril y answered by considering the semantics of equivalent higher-order functions .

Whither flowcharting

During the past few years, a growing number of authors have begun to take exception to the previously unquestioned use of flowcharts as a program development tool. These criticisms of the traditional flowcharting methodology center around the claim that flowcharts, like gotos, belong to the class of objects that are detrimental to good programming. Suggested alternatives range from developing programs entirely in well-structured high level languages to replacing conventional flowcharts by some form of “structured” flowcharts. We are particularly concerned with questions that have been raised regarding the value of flowcharting in introductory programming classes. The teaching of flowcharting as a developmental tool is extremely widespread indeed. While the various methods of indicating data flow, document flow, etc., are certainly an important part of program development and documentation, we consider here only conventional “flow of control” flowcharts.

Bessie: portable generation of network topologies for simulation

The widespread use of computer networking has resulted in considerable attention being paid to a variety of network-related problems, the generation of efficient multicast trees being one. While many algorithms for generation of multicast trees have been proposed their relative effectiveness is difficult to assess. Some algorithms have never been implemented. Many have been simulated, but often using ad-hoc networking modeling and simulation tools, without consistent parameters, making direct comparisons difficult. In this paper we discuss a network topology generation tool named Bessie, written entirely in Java. Bessie generates descriptions of random point-to-point and hierarchical networks, based on user-specified statistical parameters. We introduce a modification to Waxmans (1988) parameters, commonly used in grid-based network topology generators, which eliminates undesirable increases in node degree as the number of nodes in a network increases. The modification improves on proposed fixed scale factors.

A design approach for a distributed test automation system

An army C/sup 3/I system is a network of nodes which may be widely distributed. Validation of these systems involves exercising various configurations in the field with realistic work loads. A test automation system supports such testing by monitoring and reporting on the progress of a test and simulating portions of the C/sup 3/I system under test. A description is given of general design issues for a prototype test automation system currently under development. Particular attention is paid to the underlying software framework and to simulation aspects of the system.<<ETX>>

Reprints and resource sharing: Java as a first language: an evaluation

In this note, we outline some issues raised in considering the use of the programming language Java TM to support a first course in software development. The course essentially CS 1 is centered on the design and implementation of simple objects, and employs an iterative specify/design/implement/test strategy to introduce data design and traditional procedural concepts. We enumerate some aspects of the Java language that attracted our interest, and identify some areas of the language design that could be modified to better meet our needs in an introductory computer science