Program Development Cycle (PDLC): What You Need To Know
Any good software and web development project starts with a plan. However, many software developers try to get straight into writing code. This is wrong because an adequately planned project reduces the number of possible mistakes and makes everything straightforward.
While it’s hard to imagine that a builder builds a building without a plan — why is it so easy for a software developer to start writing code? It shouldn’t be. A proper project should be planned according to the program development cycle.
In this post, we’ll guide you in detail through the program development cycle. We’ll explain what it is, why it’s important, cover each step, and share some best practices you can follow.
What Is Program Development Cycle?
Program Development Cycle (PDLC) is a methodology that software engineers and product teams use to develop quality software. It provides a plan that breaks down program development into manageable stages and tasks. Each stage and task must be successfully completed before moving on to the next.
It may seem at first that PDLC is a sequential and linear process, but it actually requires a lot of interactions and iterations. It requires continual trial and error until you land on a program plan that works. Let’s take a look at each step of the PDLC.
The first step in the program development cycle is to define the problem. This is done by identifying and understanding why is the program or software developed. Usually, it’s in the form of a program specification. In larger development teams, the system analyst is responsible for this step.
The program specification defines the problem statement, what is required from the software development team, and what is the output of the solution to the problem they’ve been tasked with solving.
The next step in the process is to design the program itself. This process starts by focusing on the program's main goal, which the team defined in the previous step. The goal is then broken down into manageable parts, all of which play a different role in helping achieve the goal.
The first step in designing a program is to identify the main routine of the program. Then, the main routine is divided into smaller parts called modules. A lead software developer should draw up a conceptual plan for each module to visualize how it will help in the overall process.
Depending on the module, people use different types of program design tools. The five major ones are algorithms, structure charts, flowcharts, decision tables, and pseudocode.
An algorithm is a step-by-step procedure used to solve a problem in the easiest way possible. An algorithm is an exact list of instructions and can be found in everyday life, not just in software engineering.
A structure chart looks at the top-down design of the program and breaks it into the smallest functional modules. It also describes each module’s function and sub-function in detail.
A flowchart is a diagram showing the logic of the program. It can also be considered a pictorial representation of an algorithm. Each step of the algorithm is represented in the form of various shapes of boxes, with the logical flow indicated by interconnecting arrows.
A decision table is a visual representation that specifies which actions to do based on given conditions. It is divided into four parts by two horizontal and two vertical lines. Software engineers and product teams use it to settle different combinations of inputs with their corresponding outputs.
It’s informative text or annotations written in plain English and used to represent an implementation of algorithms. Since it has no syntax, it can’t be compiled or interpreted by a computer.
Coding the Program
Usually, coding itself is generally a small part of the entire PDLC. This step is completed once the entire program is codded and there are no syntax errors.
Debugging and Testing the Program
Even though one of the requirements to move onto this step is an error-free program, sometimes errors still occur. This is why the program is tested in this stage to find any logic, syntax, and other types of errors. The testing can be done internally, called alpha testing, or externally, called beta testing.
Once the errors have been found, the development team steps in to fix them.
Documenting the Program
After the testing is complete, the PDLC has reached its final stages. All the structure charts, flowcharts, decision tables, and pseudocode that were designed and used during the design phase are now part of the documentation that other people involved in the software project can use.
This phase is complete once the people working on it write a manual that includes an overview of the program, its functionalities, a beginner tutorial, explanations of significant features and all program commands, and a description of any error messages the program can generate.
Deploying and Maintaining the Program
The final step involves deploying the program for the customer. Usually, the development team keeps a tab on the project for some time, as this is usually the stage where actual usage problems can be seen.
This stage can last indefinitely, as the software needs to be maintained and upgraded regularly.
Best Practices of PDLC
To ensure that the phases and steps we laid out in this piece are followed through correctly, you should follow a few best practices. They can be applied to some or all parts of the PDLC.
Keep Your Code Simple
If you take one tip from this article, ensure it’s this one. A program with a simple code will help you stay coherent as you progress throughout the PDLC. On the other hand, a complex code can lead to a mess — one wrong input and you’ve created a domino effect.
Simple code is easy to test, it has logic boundaries on one domain, and others can easily understand it. In addition to staying coherent, simple code is more easily repurposed. Software development requires revisions and changes, and simple code will make those processes more manageable.
Follow the DRY Principle
The goal of the DRY (Don’t Repeat Yourself) Principle is to help you reduce repetition and redundancies in your software engineering process. You can do this by grouping code into functions or replacing repetitions with abstractions.
DRY helps you create a single function that performs the instruction you want to once and then references this function each time you need it instead of doing it every time. If you want to change how the function works, you’ll only need to update it once.
Use Version Control
A version control system backs up your code, makes it easy for multiple developers to work on it, and streamlines the debugging process.
PDLC is an excellent methodology for building software. For it to be successful, the entire team needs to be on the same page. If you’re still unsure about the details of the program development cycle, the following questions and answers may clarify things and help you present the idea to your team.
Q1: Why do we need program development cycles?
The most significant benefit of PDLC is that it helps create quality software. While quality software can also be created using other methodologies, PDLC simplifies it.
The other most prominent benefit of PDLC is that it’s a structured way of developing software. It eliminates almost all complications in planning, even though it requires a lot of interactions and iterations.
Q2: What are the steps of program development?
Program development consists of the six following steps:
- Problem definition: The first step, define why this software is being developed.
- Program design: Design all the steps in the process using various program design tools.
- Coding the program: Develop the software and ensure it’s error-free.
- Debugging and testing: Fix all the errors and bugs that were missed in the previous step.
- Documentation: Record in writing everything necessary for anyone using the developed software.
- Deployment and maintenance: The final step, install the software and maintain it.
Q3: What is the problem definition in a program development life cycle?
In this phase of the PDLC, people define the problem they want to deal with in the program and decide on its boundaries. This stage aims to understand the problem statement, requirements, and output, according to tutorialspoint.com.
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