7.1 The program development life cycle

## Program Development Life Cycle (PDLC)
- Analysis
- Design
- Coding
- Testing
- Maintenance
### Analysis
- Before solving a problem, it is essential to define and document the problem clearly, known as the "requirements specification" for the program.
- The analysis stage involves using tools like abstraction and decomposition to identify the specific requirements for the program.
- Abstraction focuses on the essential elements needed for the solution while eliminating unnecessary details and information.
- Decomposition involves breaking down complex problems into smaller, more manageable parts that can be solved individually.
- Tasks can be decomposed into constituent parts for easier understanding and solving.

### Design
- The program specification derived from the analysis stage is used as a guide for program development.
- During the design stage, the programmer should clearly understand the tasks to be completed, the methods for performing each task, and how the tasks will work together.
- Documentation methods such as structure diagram, flowcharts, and pseudocode can be used to document the program's design formally.
structure diagram
a hierarchical diagram showing the breakdown of a computer program into sub-programs
flowchart
a diagram showing the ordered steps to complete a computer program
pseudocode
shows what a program does in plain language
### Coding and iterative testing
- The program or set of programs is developed based on the design.
- Each module of the program is written using a suitable programming language.
- Testing is conducted to ensure that each module functions correctly.
- Iterative testing is performed, which involves conducting modular tests, making code amendments if necessary, and repeating tests until the module meets the required functionality.
### Testing
- The completed program or set of programs is executed multiple times using various test data sets.
- This testing process ensures that all the tasks within the program work together as specified in the program design.
- Running the program with different test data can identify and address potential issues and errors.
- The testing phase aims to verify the overall functionality and performance of the program by evaluating its behaviour with various inputs.