Goals

• Determine whether a problem is suitable for a computer solution
• Describe the computer problem-solving process and relate it to Polya's How to Solve It list.
• Distinguish between following an algorithm and developing one
• Apply top-down design methodology to develop an algorithm to solve a problem
• Define the key terms in object-oriented design.
• Apply object-orienteted design methodology to develop a collection of interacting objects to solve a problem
• Discuss the following threads as they relate to problem solving
  • information hiding
  • abstraction
  • naming things
  • testing

Problem Solving

• What is problem solving?
  • The act of finding a solution to a perplexing problem
• Intelligence is part of this process.
  • And as we know, the computer is not intelligent.
  • People are required to participate in computer based problem solving
• What is the computer good at doing?
  • Accurate computation
  • Very quickly
  • For long periods of time
• A Programmer (some one who writes programs) must write a program (the implementation of an algorithm in a programming language ) based on an algorithm for a problem.
• Once this is done, you can solve the problem over and over again with different inputs.
• A problem solving strategy
  • Based on a book by George Polya
  • Ask Questions - Understand the problem
    • You must understand the problem
    • You need to specify what the problem is to be able to do this
    • This is an iterative process
      • What do I know about the problem?
      • What is the information I have to process in order to find the solution?
      • What does the solution look line?
      • What are the special cases?
      • How will I recognize that I have found the solution?
    • I find
      • Write down the questions, and the answers as you find them
      • Ask the person that gave you the problem for information
      • And ask others.
      • In the beginning you should have fairly complete specifications for your problems, but this will change
      • And some of us are not good at complete specification, so you need to apply these methods anyway.
    • If you don't understand the problem, how can you solve it?
  • Look for Familiar Things
    • Have you seen this before? If so, how did you solve it then?
    • Have you done something close to this before, can you apply that method here?
  • Divide and Conquer
    • Or break the problem down into little parts
    • Don't solve the entire problem, just work on the smaller pieces.
• Algorithms
  • As we solve a problem, we produce an algorithm which later we will turn into code.
  • This is usually a repetitive process
• Computer Problem Solving
  • Three phases
  • 
    • Algorithm Development
      • Analyze the problem
      • Develop an Algorithm
      • Test the algorithm
    • Implementation
      • Translate the algorithm into code in a programming language
      • Run the program, check to see if the results are correct
    • maintenance
      • Use the program
      • Fix problems that occur
      • Add features
      • correct newly detected errors
• Following Algorithms
• Developing Algorithms
  • We will work on the the rest of the chapter
  • And probably the rest of your life.
• Problem: You would like to build a house and have a number of rectangular fields to consider as a building site.