Program Development Life Cycle

• Problem solving helps in formulating the best solution.
• A computer program is the product of problem solving.
• Computing uses the Program Development Life Cycle to solve problems.
• The Program Development Life Cycle is a methodology to develop a program in any programming language.

6 Phases of Program Development Life Cycle

• Problem Definition.
• Problem Analysis.
• Algorithm Development.
• Coding and Documentation.
• Testing and Debugging.
• Maintenance.

Phase 01: PROBLEM DEFINITION

• The first step involves defining the problem and its boundaries.
• A clear understanding of the problem statement, requirements, and output is needed.

Phase 02: PROBLEM ANALYSIS

• Program requirements like variables and functions are distinguished.
• Gathering required resources and defining solution boundaries are included.

Phase 03: ALGORITHM DEVELOPMENT

• Involves developing a step-by-step procedure to solve the problem.
• This phase results in the blueprint of the code.

Phase 04: CODING AND DOCUMENTATION

• The program is written using a programming language.
• Actual programming codes are defined in the algorithms produced in the previous phase.
• Languages like Python, C++, and Java can be used.

Phase 05: TEST and DEBUGGING

• The code is checked for bugs and errors.
• Errors and bugs are fixed, and inaccurate results corrected.
• Grace Brewster Hopper coined the term "BUG".

Phase 06: MAINTENANCE

• The program is implemented and actively used.
• Bugs found at this stage are fixed and necessary enhancements are made.

Problem Analysis Chart (PAC)

• A tool that helps in defining the output and input of a problem.
• Input is the data provided to the program, including constants and variables.
• Output includes the requirements for the output reports.
• Processing Required: List of processing required including equations or other types of processing
• Solution Alternative: List of ideas for the solution of the problem

Example Problem: Convert Minutes into Seconds

• Input: Minutes.
• Output: Seconds.
• Processing: Seconds = Minutes * 60.
• Solution: Define Minutes as constants.

Example Activity: Perimeter of a Rectangle

• The program takes the length and width of a rectangle and returns its perimeter.
• Input: Length and width.
• Output: Perimeter.
• Processing: P = 2l + 2w.
• Solution: Define Minutes as constants.

Algorithm Development

• Involves breaking down tasks into a series of steps.
• Algorithms are a set of step-by-step instructions.
• In computer science, algorithms are specific instructions and operations for a program.
• Each step in the algorithm should be clear and unambiguous.
• Each instruction should start with a verb.

Desk-Checking the Algorithm

• The programmer reviews the algorithm while seated at their desk.

Pseudocode

• It is a way of describing instructions without specific rules.
• Can be written in consecutive phrases with logical flow emphasized by indentation.
• Used to create models or mock-ups of programs.

Pseudocode Example: Convert Minutes to Seconds

• Input: Minutes.
• Output: Seconds.
• Processing: Seconds = Minutes * 60.
• Solution: Define Minutes as constants.

Pseudocode Example: Perimeter of a Rectangle

• Input the value of length and width.
• Compute the perimeter as twice the length plus twice the width P = 2(length) + 2(width).
• Display the value of the perimeter as a result.

Basic Pseudocode Structure

• Get the data.
• Perform the computations.
• Display the result.
• INPUT: Indicates a user input.
• OUTPUT: Indicates an output on the screen.
• WHILE: A loop with a condition at the beginning.
• FOR: A counting loop.
• REPEAT UNTIL: A loop with a condition at the end.
• IF THEN ELSE: A decision in which a choice is made.

Flowcharts

• Visual representation of an algorithm using symbols.
• Helps communicate the solution steps.
• Flowcharts flow from top to bottom and left to right.
• Start/Stop: Marks the beginning and end of the program.
• Input/Output: Represents steps that read input or display output.
• Process: Represents steps performing calculations.
• Decision: Shows decision-making steps.
• Flow: Connects the steps in a flowchart.
• On-Page Connector: Used to replace long lines on a flowchart on the same page.
• Off-Page Connector: Used when the target is on another page.
• Declare: Used to declare variables in the flowchart.