Introduction to Computer Information Systems/Program Development. Program Design and Development. This was a much older type of programming language that has since been outdated by object oriented programming. However this type of programming is very important and should be well understood if you want to understand the concepts of programming and what all goes into it. This process is also called imperative programming in some contexts, meaning top- down languages; this is how the programming functions, from a top to bottom procedural order. This is what makes this process self- explanatory in a way, because in order for something to work and pass along a message we assume it to go in this order. Design (write down how it should work), Implement (create some code), Test (make sure it works), Deploy (send it to the users), Maintain (fix bugs). Testing in the Software Lifecycle. The study of this cycle has come to be called 'devOps.'. Testing in the development cycle. Along with going step by step in order to solve a problem, the list of instructions must be sent to the computer in order for it to know what to do with this information. It relies on routines, or procedures, that have multiple steps that need to be carried out. Procedural programming has been somewhat of a stepping stone for other types of programming because of its simplicity. It is an older type of programing and is now outdated by another popular form which is object oriented programming. An object, such as a person, should have a name, or be able to walk, which can be seen as a method in oriented programming. Having a method is this programming is like having a procedure in procedural programming. Objects within an object oriented program consists of attributes. The development phase fleshes. Policy Program Office; BA. Technology in Action Chapter 10. Which step in the program development cycle involves designing a set of steps. That point in the release cycle is called RTM. Software life cycle models describe phases of the software cycle and the order. If you have ever played D& D. If you have an object you can change its attributes like size, shape, and color. Aspect Oriented Programming is a form of programming that compliments Object Oriented Programming (or OOP) by allowing the developer to modify OOP in a way where the system can grow to meet new requirements. It keeps the original model, which was developed in OOP, but allows for new syntax without having to change the compiler being used or reconfigure the editor either. In essence, it is complimentary to the previously developed OOP style and allows the application to adopt new characteristics over its lifetime without having to be completely remodeled or redeveloped. This ability for an application to be adapted to the current trend in technology prolongs the usefulness and life span of the application, which then benefit the users of that application as well. A mission is still defined; it is just acknowledged that the mission can never be inclusive of all possible outcomes and may need to be changed. This can be difficult, because, per this model, that environment is often at the . Finally, there is a focus on learning from mistakes on the part of both the developers and the consumers. These three- phase cycles are short so that small mistakes, not large ones, are the ones from which lessons are learned. The computer user must figure out the problem, and the best program to fix it. Design the program. A flow chart is important to use during this step of the PDLC. This is a visual diagram of the flow containing the program. All in all, this step is breaking down the problem. This is using the language of programming to write the lines of code. The code is called the listing or the source code. The computer user will run an object code for this step. The computer user must debug. This is the process of finding the . The bugs are important to find because this is known as errors in a program. Formalize the solution. One must run the program to make sure there are no syntax and logic errors. Syntax are grammatical errors and logic errors are incorrect results. Document and maintain the program. This step is the final step of gathering everything together. Internal documentation is involved in this step because it explains the reasoning one might of made a change in the program or how to write a program. This language is similar to English and has been converted to machine language using a type of program known as a compiler. Because code is used to instruct computers to perform a wide array of tasks, there are many different kinds of languages and programs available. One of the most important aspects of coding is deciding which jobs (creating a web page, writing a game, etc.) a computer will do. Regardless of what is chosen, the majority of codes utilize plain- text because of its compatibility. Though the actual content is written this way, documents are each given a unique file extension that is indicative of their type. One can write a simple code with a basic word processor or text editor. However, using a software application (specifically designed for coding in a particular language) is significantly more effective and efficient. As with a document written in English, where word processing software is used to aid in detection of spelling errors and non- standard grammar, a coding editor provides comparable tools to ensure accuracy. A code editor is also known as an integrated development environment (IDE), which is a software application for formatting. A large downfall of working with IDEs is a lack of flexibility. While some IDEs work with multiple programming languages, a sizable amount are very specific for only one language. Certain tools such as flowcharts and pseudocode are used to simplify the design process and allow the developers to see the program before any actual coding is used. A common type of design tool is the flowchart. A flowchart can be either handwritten or created with software such as Visual Logic or Flowgorithm . Flowcharts are also useful for education tools because they focus more on the concept of programming rather than focusing on the syntax of languages. Another type of design tool is pseudocode. Pseudocode is very similar to a programming language except that it uses non- syntactical words to summarize the processes of a program. Pseudocode cannot be compiled or executed but it does serve as a good starting point for programmers. When executing (running), the compiler first parses (or analyzes) all of the language statements syntactically one after the other and then, in one or more successive stages or . A compiler works with what are sometimes called 3. GLs (FORTRAN, BASIC, COBOL, C, etc.) and higher- level languages. The compiler frontend analyzes the source code to build an internal representation of the program, called the intermediate representation. The compiler backend includes three main phases, such as analysis, optimization, and code generation. For example, there is a FORTRAN compiler for PCs and another for Apple Macintosh computers. In addition, the compiler industry is quite competitive, so there are actually many compilers for each language on each type of computer. More than a dozen companies develop and sell compilers for the PC. The diagram shows exactly when an instruction is performed, and how it. Most importantly, a control structure shows the order of the instructions. Choosing a specific control structure depends on what you want the program or module to accomplish. A sequence control structure is the simplest and least complex control structure. Sequence control structures are instructions that are executed one after another. A more complex control structure might be a selection control structure, a structure that involves conditions or decisions. This means that the structure can allow different sets of instructions to be executed depending on whether a condition is true or false. This control structure is used when repeating a group of code is necessary. The code will be repeated until a condition is reached. Repetition control structures are used when looping is needed to reach a specific outcome. The program design is very important, especially because it involves the overall step- by- step directions regarding the program. A programmer must test the program design to ensure that it runs correctly and that there are no mistakes. The operation a programmer must do to complete this task is called desk checking. Desk checking allows the programmer to run through the program design step- by- step. Essentially, the programmer runs through lines of code to identify potential errors and to check the logic. The programmer uses tracing tables to keep track of any loop counters. The goal of checking the program design is to avoid running into mistakes further on in the program development cycle. The sooner the mistake is caught in the development cycle the better. If the error is not found until later in the developmental cycle, it may delay a project. Therefore, a programmer must make sure they pay strict attention while desk checking. Advantages to desk checking include the convenience of hands- on . The programmers wrote the code themselves, so it is an advantage that they can work immediately with familiar code. A disadvantage to the desk checking system includes potential human error. Since a computer is not checking the design code, it is prone to human error. Debugging is a large part of what a programmer does. The first step to debugging is done before you can actually debug the program; the program needs to be changed into machine language so that the computer can read it. It is converted using a language translator. The first goal of debugging is to get rid of syntax errors and any errors that prevent the program from running. Errors that prevent the program from running are compiler errors. These need to be removed right away because otherwise you cannot test any of the other parts of the program. Another kind of error is a runtime error, which occurs while the program is running and it is not noticed until after all syntax errors are corrected. Many run time errors are because of logic errors, which are errors in the logic of the program. It could occur when a formula is written incorrectly or when a wrong variable name is used. One technique called print debugging, or also known as the printf method, finds errors by watching the print (or trace) statement live or recorded to see the execution flow of the process.
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