The Programming Development Life Cycle (PDLC)
Programming can be defined as the development of a solution to an identified problem, and the setting up of a related series of instructions which, when directed through the computer hardware, will produce the desired results.
The notification that there is a problem can come from a systems analyst, an end user, or management. The problem needs to be defined so that the correct solution to solve it can be a program. Once a program is written, it is correct if it does what it is supposed to do. Before a programmer ever sits down to code (write the program, using a programming language), he will first write the program out on paper. He will then look at each line that he has written (this is called desk checking or tracing) to make sure that each line will do what is expected and that the program will achieve the desired results. Only after tracing the program and testing that the logic works, will the programmer code the program. The formal creation process of programming is known as the PDLC, the programming development life cycle. There are seven steps to this: define, outline, develop, test, code, run, and document and maintain. These are the steps that you will take to develop your projects. As the semester progresses, we will look into these topics more in depth. Define - to decide what real world problem is to be solved and how a program can do this. The decisions of what the program should do. Looking at the flow of the data, the form of the input and output, the process needed and the user interaction. A defining diagram helps the programmer to see the components. If I were asked to write a program which would compute the cost per square foot of living space for a house, given the dimensions of the house, the number of stories, the size of the nonliving space, and the total cost of the land, I would know that any noun or adjective is input or output and any verb is process.
|Input |Processing |Output | |Width of the house |Calculate cost per foot |Gross footage | |Length of the house |Calculate living area | | |Number of stories |Calculate gross footage | | |Size of nonliving space | | | |Selling price, less land | | |
Outline – breaking a large problem up into smaller ones. Deciding what the steps of the program are. A tool that is available to help the programmer during this step is a Flowchart, which is a visual diagram of the flow of the program. Develop the Algorithm - An algorithm is the steps that a programmer will write that will become a program. It is written in a form of structured language called Pseudocode. Pseudocode is language nonspecific; it could be used by any programmer to help him or her write the actual program using any programming language. Each step of your algorithm will be directly translated into a line of code when it is time to write the program using the programming language. Did you get that important point? One line of the algorithm is equal to one line of the code. Algorithms are written in sequential order of action and are language non-specific. If an algorithm is written correctly, any programmer using any language could directly translate each line of the algorithm into a line of code. If the algorithm is correctly written, the programmer knows that the program will work. It is possible to desk check the algorithm; it saves a programmer a lot of...
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