CSCI110 EventDriven Programming Using Visual Basic

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CSCI110 Event-Driven Programming Using Visual
Basic
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• Problem Solving

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Problem Solving

• The problem solving techniques introduced here
  can be applied to most kinds of problems, not
  just problems to be converted into computer
  programs.

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A typical problem at the college

• How to switch on in to a computer in a
  Computer Science room in this college, and start
  up the Notepad program to write and save a
  document to any directory on the computer.

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Exercise

• Using Notepad, write a document to solve the
  problem shown on the previous screen.

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Problem Solving and Computer Programming

• Algorithms
• Program Design
• Software Lifecycle

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Algorithms

• An algorithm is a sequence of precise
  instructions (written in English) that leads to
  the solution to a problem.
• An algorithm can be compared to a recipe to
  bake a cake, a set of directions to enroll for a
  class or a set of instructions to install an
  operating system...

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Program Design

• problem solving phase
• (results in an algorithm)
• implementation phase
• (results in the program developed from
  the algorithm)

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Software Lifecycle

• 1. Problem definition
• 2. Algorithm design
• 3. Coding
• 4. Testing
• 5. Maintenance

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(No Transcript)
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• Table 1 Relative costs of software systems
• System Type Phase costs ()
  ___________________________________
  ___
  
• Design
  Coding Testing
• Control system 46 20 34
• Spaceborne system 34 20 46
• Operating system 33 17 50
• Scientific system 44 26 30
• Business system 44 28 28

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Data from Table 1

• Boehm,B.W. (1981) Software Engineering
  Economics, Prentice Hall

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Note!

• According to the data in Table 1, when you are
  developing a computer program, you should be
  spending only one quarter of the time on actually
  typing in the computer program (aka code)! This
  is called the implementation stage.
• Most of the time should be spent on design
  and testing.

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Design and Testing

• The Design and Testing stages in the
  development of any computer system (program) are
  the most expensive stages.

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Tools for Software Design

• Flowcharts
• Pseudocode
• Hierarchy Charts

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Documentation

• Any paperwork associated with a computer
  program is know as external documentation
• Internal documentation are any comments you
  make in the program code itself...

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Documentation

• Requirements Phase (what the program has to do)
• Design Phase (how it will do it)
• Coding Phase (the code itself)
• Testing Phase (the test data and results)
• Operation Phase (the user manual)

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Tools for Software Design

• Flowcharts
• Pseudocode
• Hierarchy Charts

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Start
input 3 numbers
Flowchart of a program to calculate the average
of 3 numbers
calculate total
divide total by 3
output result
End
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input the numbers calculate the total calculate
the average output the result
Pseudocode of a program to calculate the average
of 3 numbers
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Hierarchy chart of a program to calculate the
average of 3 numbers
Calculate average of 3 numbers
print out the result
divide the total by 3
calculate the total
input the numbers
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• End of VB_ProblemSolving.ppt

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• Last updated Friday 2nd January 2009, 1545 PT
  by AHD