COP 1002: Structured Programming

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COP 1002 Structured Programming

• By Ali Fazelpour

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Definitions

• System A combination of people, equipment, and
  procedures that work together to perform specific
  functions
• Computer-based Information system Some
  procedures are performed by a computer

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System Development Life Cycle (SDLC)

• Analyze the current system
• Define the new system requirements
• Design the new system
• Develop the new system
• Implement the new system
• Evaluate the new system

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SDLC

• Analyze the current system
• System Analyst Every aspects of an existing
  system to see What/How
• Users Day-to-day activities

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SDLC

• 2. Define the new system requirements
• What needs to be done
• Eliminate current problems
• Input/Output requirements
• Reports/Screen designs
• Storage/Processing requirements
• What files/What data in each file

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SDLC

• 3. Design the new System
• System Analyst/System designer
• Use the requirements defined in the second step
  for designing new or modified system
• Several tools will be used for this purpose
• System flowchart Pictorial presentation of a
  system Input/Process/Output
• No Details at all
• Fig 1.2 Page 3
• Computer-Assisted software engineering (CASE)
  To refer to automation of tools, methods and
  procedures for system development

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SDLC

• 4. Program Development Cycle (PDC)
• Fig 1.3 Page 4
• Programmer
• 4.1 review the program requirements
• 4.2 Develop the program logic
• Fig 1.4 Page 5 Program Flowchart Pseudocode
  
• Structure chart modularization Chapter 5
• Fig 1.6 Fig 1.7 Page 7 User-friendly
  Software Graphical User Interface

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SDLC PDC

• 4.3 Write the program
• Procedure-Oriented Language
• 4th generation language What to do/NOT How to do
• Object-Oriented Programming
• 4.4 Test and debug a program
• Syntax error
• Logical error
• Unit testing
• System testing (Integration)

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SDLC PDC

• 4.5 Complete the program documentation
• Ongoing process
• A technical reference for programmers
• User Guides How to use operate the system
• Hard copy vs. Online help

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SDLC

• 5. Implement the new System
• User training/Define operating procedures
• System documentation reviewed/revised
• New system runs in parallel with old
  system/replaced it/or phased in gradually

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SDLC

• 6. Evaluate the new system
• The new system meets the required objectives
• Modification if it is necessary
• System evaluation report for management

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Structured Programming

• To express a solution using only 3 basic pattern
  of logic
• Patterns are called Control Structure
• Patterns are based on computers ability to
  execute instructions in a step-by-step,
  sequential manner Simple Sequence Control
  structure
• Its ability to make decisions IFTHENELSE Control
  Structure
• Its ability to repeat instructions DOWHILE
  Control Structure

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Three basic Control Structures

• Simple Sequence Step-by-step, in a sequential
  manner
• IFTHENELSE to make decision
• DOWHILE to repeat a series of instructions
  repeated instructions is called Loop.
• Infinite loop Never Ends. It is a logical error.