Chapter 2

1. IPO Charts
   

   Input	Processing	Output

   
   
   
2. Problem Solving Process
   1. Analyze the problem also call ed the specification.
      1. In practice this is the hardest step.
      2. The specification drives everything else.
      3. When Ford produced Pintos, the manufacturing plant produced the cars according to the specification.
      4. In this course the complete specification for the assignments and examples will be clear and unambiguous. This is rarely the case outside of academia
      
      
   2. Plan the Algorithm Also called the design step
      1. Top - down.
      2. Decomposition
      3. Abstraction
      4. Rapid Prototyping.
      
      
   3. Desk Check the Alogrithm
      
      
   4. Code the Algorithm also called Implementation
      1. Bottom - Up Implementation
      2. Function stubs.
      3. Function Drivers.
      4. Hollywood style of tackling functions.
      
      
      
   5. Desk check program
      
      
   6. Evaluate and modify the program, the iceberg effect.

3. Bumper Sticker Computer Science
   • When in doubt, use brute force - Ken Thompson Bell Labs
   • The sooner you start to code, the longer the program will take. - Roy Carlson UW
   • If you can't write it down in English, you can't code it. - Peter Halpern
   • If the code and comments disagree, then both are probably wrong. - Norm Schryer Bell Labs
   • If you have too many special cases, you are doing it wrong. - Craig Zerouni
   • Get your data structures correct first, and the rest of the program will write itself. - David Jones
   • Don't make the user provide information that the system already knows. - Rick Lemmons
   • Of all my programming bugs, 80% are syntax errors. Of the remaining 20%, 80% are trivial logical errors. Of the remaining 4%, 80% are pointer errors. And the remaining 0.8% are hard. - Marc Donner IBM
   • Testing can show the presence of bugs, but not their absence. - Edsger Dijkstra
   • The first 90% of the code accounts for the first 90% of development time. The remaining 10% of the code accounts for the other 90% of the development time. -Tom Cargill
   • Good judgment comes from experience, and experience comes from bad judgment. - Fred Brooks
   • Whenever possible, steal code. - Tom Duff
   • Make it work first before you make it work faster. - Bruce Whiteside
   
   
   
4. Examples.
   • The Bear
   • Square Mile of Land
   • 8 Billard Balls
   • Tainted Medicine.
   
   

5. Exercise #1 page 61.

   Input	Processing	Output
   Number	Start Get a Number Compute the Square of Number     as Number * Number Display the Square of the Number. Stop	Square of Number

   
   

6. Exercise #3 Pages 61.

   Input	Processing	Output
   Sales Rate	Start Get the Rate Get the Sales Compute the Commission as    Sales * Rate Display the Commission Stop	Commission

7. Exercise #5 page 62.

   Input	Processing	Output
   Number	Start Get a Number If Number less than or equal to 0    Display Error Message Otherwise    Compute the Square of Number       as Number * Number    Display the Square of the Number. EndIf Stop	Square of a number

8. The the Squares of the numbers between 10 and 20.

   Input	Processing	Output
   	Start Number = 10 While Number less than 20    Compute the Square of Number       as Number * Number    Display the Square of the Number.    Add 1 to Number EndWhile Stop	Squares

   
   Does this work correctly?

   ---