Problem Solving and Programming

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Problem Solving and Programming Problem Solving

• Dr Scott Turner

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Why do you needed to develop problem solving
skills?

• One definition of programming is it is applied
  problem solving
• You have a problem (E.g Need a program to
  calculate the area of the circle).
• What needs to be done?
• What inputs and outputs are needed?
• How does what is entered produce the right output?

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• many students have almost no mathematical
  background and some even arrive with a built-in
  phobia against anything involving formulae or
  syntax. Carter (2004)

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• Programming is a complex activity. Problem
  Solving is not trivial and requires component
  skills including relativity decision making
  identification of the central issues recognition
  of relationships, familiar situations and
  patterns development of an algorithm and the
  translation of the algorithm into executable
  code. Beaumont and Fox (2003)

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• Beaumont C and Fox C (2003) LEARNING
  PROGRAMMING ENHANCING QUALITY THROUGH
  PROBLEM-BASED LEARNING. online 4th Annual
  conference of the LTSN Centre for Information and
  Computer Science Galway 26-28th August 2003
  http//www.ics.ltsn.ac.uk/pub/conf2003/index.htm
  accessed on 16th October 2003
• Carter C (2004) Say it another way Sam
  Different Learning Paths online LTSN-ICS One
  Day Workshop on the Teaching of Programming
  university of Huddersfield 15th March 2004
  http//www.ics.ltsn.ac.uk/pub/programming04/index.
  html accessed on 16th July 2004.

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Mistakes

• An expert is a man who has made all the mistakes
  which can be made in a very narrow field.
• Niels Bohr

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Mistakes

• Anyone who has never made a mistake has never
  tried anything new. Albert Einstein

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Simplicity

• Any intelligent fool can make things bigger and
  more complex... It takes a touch of genius - and
  a lot of courage to move in the opposite
  direction. Albert Einstein

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Simplicity

• Everything should be made as simple as possible,
  but not simpler. Albert Einstein
• All quotes taken fromhttp//www.brainyquote.com/
  Accessed on 18/9/2006

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How do this course split

• Weeks 1-8
• Problem Solving
• Weeks 9-24
• Java Programming

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Stepwise refinement

• Take the problem and break it down in to smaller
  and smaller chunks that are now manageable.

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Basics

• Problem statement
• Analysis
• Design
• Implementation
• Testing

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Analysis Sample thoughts

• What does it have to do?
• What does it need?
• What rules/algorithms are needed?
• When testing what does it take to prove it works?
• Can I break this down further?

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Things to remember

• There is often more than one solution to a
  problem
• You can often solve a problem in many different
  ways, that each have advantages and
  disadvantages.
• Two heads are better than one
• Part of some problem solving techniques can be as
  simple as discussing issues.
• For example Why did you do that?

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Problem 1.1

• Write a routine to calculate the area of the
  circle.
• First pass
• Input
• Calculation
• Display

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• Second pass
• Input
• Input radius of the circle
• Calculation
• AreaPi x radius x radius
• Display
• Display area on the screen

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• Third pass
• Put a message of the screen telling the user to
  enter the radius of the circle.
• Read in from the keyboard what the radius of the
  circle is
• Calculation AreaPi x radius x radius
• Display the following message on the screen The
  area of the circle is and display the result of
  the calculation on the screen

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Problem 1.2

• In groups of 2-3 write a routine for calculating
  the area of a rectangular room.
• First pass
• Input
• Calculation
• Display

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What assumptions did you make?

• Did you assume that the measurements of the room
  were already taken?
• What units of measurement did you use?
• What does area of the room mean?
• Area of the floor?
• Area of the floor and area of all the walls?

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Problem 1.3

• An Ant is in the corner of the a sqaure room.
  (taken orginally from Vickers P (2009) How to
  Think Like a Programmer ISBN 978-84480-903-5
  Cengage)
• Goal Is to get to a bowl of sugar in the
  opposite diagonal corner on the floor. What is
  the shortest route?
• Restrictions It cant fly or be blown across the
  room

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Hints

• The key to this problem is to re-arrange the
  problem.
• Try flattening the walls.

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University of Minnesota Five steps in problem
solving

• Understand and isolate the problem
• Brainstorm for ideas to solve the problem
• Design a solution that might work
• Test your solution to see if it will work
• Assess whether the solution is good enough to do
  it
• See http//cda.mrs.umn.edu/fauxr/computing/proble
  msolve.html

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Understand and isolate the problem

• What does it take to succeed with a particular
  problem?
• What is the vital information?
• Identify the parts of the problems analysis.
• What are the inputs and outputs?

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Understand and isolate the problem

• Identify the parts of the problems analysis.
• What are the inputs and outputs?
• What are the limitations?
• What are the rules?

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Brainstorm for ideas to solve the problem

• Note down all the solutions
• Have solutions been used in similar way before?
• Keep solutions that have common features .
• Two heads are better than one.
• When all the solutions have been found weed-out
  less reasonable ones.
• Can be solo or group activity.

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Design a solution that might work

• The design of a solution can be created using
  diagrams, algorithms and other models. The main
  purposes of creating a design that can be viewed
  by others is to communicate the solution.
  Providing a diagram or algorithm of what you
  THINK is going on and is needed will provide
  others a chance to see what your thinking is.

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Test your solution to see if it will work

• Take the time to trace through your design with
  some test information.
• Try more than one scenario.
• Try to find information that tests the borders.
• Choose some information that isn't supposed to
  work and be certain that the design handles it.
• Give your algorithm or diagram to another person.
•  

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Assess whether the solution is good enough to do
it

• Is this solution really worth doing?
• Would another solution be better for this
  situation?

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Problem 1.4

• Write a routine that lets the user convert pounds
  Stirling into the Northampton dollar and display
  the results
• What information do you need?
• What does the routine need to do?