12.1 Program Development Life cycle

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What is the program development life cycle?

The program development life cycle is a structured way of creating a program. In simple words, it is a set of stages that developers follow so they can build software in an organised and sensible way.

Instead of starting to code immediately, developers work through a clear process. This helps them understand the problem properly, plan the solution, build the program, check that it works, and keep it useful after it has been released.

A life cycle is important because real programs are usually made for other people to use. That means the work must be clear, organised, and properly documented. Different developers may work on the same program, either now or later. If the work is messy or unclear, it becomes hard to improve, fix, or understand.

It is called a life cycle because the work does not stop when the program is first finished. A program may need changes later. New problems may appear. Users may want extra features. Hardware or software may change. So the program keeps being checked and updated while it is still in use.

The purpose of a program development life cycle

The main purpose of a program development life cycle is to make sure software is developed in a clear and ordered way.

This matters for several reasons.

First, it helps developers understand exactly what the program is supposed to do. If the problem is not clearly understood at the start, the finished program may solve the wrong problem.

Second, it helps with planning. A program often has many parts, so developers need a sensible order for doing the work.

Third, it helps with communication. When the stages are documented properly, other developers can understand the program and continue the work if needed.

Fourth, it helps produce a more reliable program. Because the work is broken into stages, problems can be found and fixed more easily.

Finally, it supports change. Most programs are not used exactly the same way forever. A good life cycle makes it easier to correct errors, improve features, and adapt to new requirements.

So, the program development life cycle helps to make software that is:

• organised
• documented
• easier to manage
• easier to test
• easier to improve later

1. Analysis

The analysis stage is about understanding the problem before any solution is built.

Before developers can make a program, they must know exactly what is needed. They must find out what the user wants the program to do, what inputs and outputs are needed, and what limits or rules the system must follow.

A key part of analysis is creating the requirements specification. This is a document that clearly states what the program must do. It explains the needs of the user and defines the features the program must include.

The analysis stage may begin with a feasibility study. This is a check to see whether the program is practical to create. For example, developers may think about cost, time, available staff, and available hardware.

After that, developers carry out investigation and fact-finding. They may speak to users, observe how the current system works, or examine the problems with the old system.

At the end of analysis, the team should understand:

• the problem to be solved
• the tasks the program must perform
• the limits the program must work within
• the success criteria for the finished program

If analysis is poor, the rest of the project is likely to go wrong, because the program may be built on incorrect or incomplete requirements.