Computer Systems Module 5: Algorithm Development

Introduction to Computer Systems - Module 5: Algorithm Development

• Objectives: Recognize the program development life cycle, select appropriate computer-based methods for modeling and analyzing problems, and differentiate between algorithm, pseudo code, and flowchart.

Software Development Life Cycle (SDLC)

• Planning (Problem Definition): Define the problem, its boundaries, requirements, and desired output. This is the initial phase of program development.

• Problem Analysis: Precisely define the problem, including inputs, processing, outputs, and user interface specifications.

• Design: Develop a detailed logic plan using tools like pseudocode, flowcharts, object structure diagrams, or event diagrams to organize program activities into modules, defining solution algorithms for each module and testing these algorithms.

• Implementation: Translate the design into a working application using a programming language or application development tool. Include user interface development and code documentation with comments and remarks explaining the code's purpose.

• Testing and Integration: Test the program, identify and correct errors (debugging) until error-free and achieving the desired results.

• Maintenance: Provide education and support to end-users, correct any issues, and handle modifications or enhancements. If necessary, the SDLC begins again at the Planning step.

• Retirement (Unofficial): The software's lifecycle concludes when the software is no longer supported or is replaced. Stakeholders may decide to create an entirely new replacement application.

Documentation

• Purpose: Compile materials generated throughout the SDLC process, including flowcharts, messages, algorithms, code, and user manuals.

• Internal Documentation: Used by programmers to understand the rationale behind code decisions and program design.

• External Documentation: Includes user manuals, FAQs, and help resources on a website, clarifying the software's functional aspects beyond the coding itself.

Algorithm

• Definition: A sequence of well-defined, unambiguous, finite instructions for accomplishing a task. The term derives from Muhammad ibn Musa al-Khwarizmi.

Algorithm (Example) - Finding the area of a circle

• Problem: Calculate the area of a circle with radius 'r'.

• Input: Radius 'r'

• Output: Area of the circle

• Algorithm Steps:

  • Read the radius 'r'
  • Calculate Area = 3.14 * r * r
  • Print the calculated area

Algorithm (Example) - Finding the greatest among three numbers

• Algorithm 1:

  • Read three numbers (A, B, C)
  • Compare A and B; if A > B, proceed to step 3, else go to step 4.
  • Compare A and C; if A > C, output "A is greatest", else output "C is greatest".
  • Compare B and C; if B > C, output "B is greatest", else output "C is greatest".

• Algorithm 2:

  • Read three numbers (A, B, C)
  • Compare A and B, store the greater in MAX.
  • Compare MAX and C, output the greater as "greatest".

Algorithm (Control Structures)

• Sequential: Instructions are executed in the order they are written.

• Selection (Conditional): A true/false decision determines the next instruction sequence.

• Iterative (Loop): Repeats a block of instructions.

Flowchart

• Definition: A diagrammatic representation of algorithm logic for task solutions. Includes standardized symbols for various actions, decisions, connectors, and data flows.

Flowchart (Control Structures)

• Sequence: Instructions executed one after another.

• Selection: Decisions based on conditions determine program flow.

• Iteration: Loops repeat instructions based on conditions.

Pseudocode

• Definition: A readable, informal language that describes an algorithm's steps using English-like statements and programming-like constructs and actions. -Common terms represent fundamental processing tasks.

• Examples of Specific Pseudocode Operations (input/output, calculation, etc.):

  • READ
  • COMPUTE
  • PRINT/ OUTPUT/DISPLAY
  • INCREMENT, INITIALIZE

Pseudocode (Control Structures)

• IF/THEN/ELSE: Conditional execution.

• CASE: Selection among multiple conditions.

• WHILE: Repeated execution as long as a specific condition is true.

• DO WHILE: Alternative syntax for repeating code based on a condition.

This quiz covers Module 5 of Introduction to Computer Systems, focusing on the program development life cycle and algorithm development. Explore the essential steps, including planning, problem analysis, design, and implementation. Understand the distinctions between algorithms, pseudocode, and flowcharts essential for effective programming.