Languages like java or C++ this section presents a brief over view of various programming approaches. Systems professionals will make their decision based on the in-house standards.
Architecture, and user needs
Procedural languages. A procedural language requires the programmer to specify the precise order in which the program logic is executed. Procedural languages are often called third-generation languages (3GLs). Examples of 3Gls include COBOL, FORTRAN ,C ,and PL1.In business(particularly in accounting) applications , CoBOL was the dominant language for years. CoBOL has great capability for performing highly detailed operations on individual data records and handles large files very efficiently . however ,it is an extremely “wordy” language that makes programming a time- consumingtask . CoBOL has survived as a viable language because many of the “legacy system” written in the 1970s and 7980s. which were coded in COBOL, are still in operation to day. Major
Retrofits and routine maintenance to these system need to be coded in COBLO. Upward of 12 billion
Lines of COBOL code are executed daily in the united states.
Event-driven languages event-driven languages are no longer procedural. Under this model, the program’s code is not executed in a predefined sequence. Instead ,external actions or “ event ”that are initiated by the user dictate the control flow of the program for example where the user
Presses a key or “click” on an icon on the computer screen the program automatically executes code associated with that event. This is a fundamental shift from the 3GL era now instead of designing applications that execute sequentially from top to bottom in accordance with the way the programmer thinks they should function the user is in control
Microsoft’s visual basic is the most popular example of an event-driven language the syntax of the language is simple yet powerful visual basic is used to create real time and batch applications that can manipulate flat files or relational databases it has a screen-painting feature that greatly facilitates the creation of sophisticated graphical user interfaces(GUI).
Object-oriented languages central to achieving the benefits of the object oriented approach is developing software in an object-oriented programming (OOP) language the most popular true OOP
Languages re java and smalltalk . However the learning curve of OOP languages is steep. The time and cost of retooling for OOP is the greatest impediment to the traditional process. Most firms are not prepared to discard millions of lines of traditional COBOL code and retrain their programming staffs to implement object-oriented systems. Therefore, a compromise, intended to ease this transoton , has been the development of hybrid languages such as object COBOL object pascal, and C++
Programming the system regardless of the programming language used, modern programs should follow a modular approach this technique produces small programs that perform narrowly defined tasks . the following three benefits are associated with modular programming
1. Programming efficiency. Modules can be coded and tested independently, which vastly reduces programming tune A firm can assign several programmers to a single system working in parallel the programmers each design a few modules these there are then assembled into the completed system.
2. Maintenance efficiency. Small modules are easier to analyze and change, which reduces the start-up time during program maintenance .extensive changes can be parceled out to several
Programmers simultaneously to shorten maintenance time.