CS 151 Fall 2003

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CS 151 - Fall 2003

• Things we didn't have time to cover

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Bits of C we didn't cover

• We've covered most of the C language, just a few
  small items
• Lots of libraries we didn't cover
• Small bits of syntax, such as the enuemration

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Enumerations

• A way to make a small discrete set of values
• enum colors Red, Blue, Yellow
• enum days Monday, Tuesday, Wednesday
• creates a new set of constants (Red, Blue, etc)
  and a new type (colors)

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Creating variables of type

• Can create variables of the type
• enum colors myFavoriteColor
• myFavoriteColor Red
• unfortunately, doesn't print the way you would
  expect

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printing enumerations

• printf("My favorite color is d",
  myFavoriteColor)
• myFavoriteColor is 3
• shows that under the hood enumerations are just
  integers. No, it cannot be printed as a string.

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Bigger Topics

• Programming C is just the first tiny step on the
  path to computer science.
• How to organize and structure large tasks,
  perhaps involving many programming - software
  engineering
• Other programming languages and styles, OOP,
  functional programming, logic programming

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Software Engineering

• Programming is similar to other engineering
  activities (building bridges) and in some ways
  very different.
• Example Adding people to a programming team will
  often make it go more slowly, not faster.

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One Saying

• Fred Brooks used to say
• "It takes nine months to create a child, no
  matter now many women are assigned to the task"
• Major problem in software teams in communication,
  not programming - gets worse more people you have

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So how to you handle complexity?

• So how do you handle complexity?
• Better languages, better tools, better
  organizational techniques
• Will see this in many of your future classes.

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Languages

• While C is a good place to start learning about
  langauges, not the final word
• Object-Oriented Languages, Functional Languages,
  Logic Languages, Scripting Languages,
  Coordination Languages, visual languages, etc etc

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Object-Oriented Languages

• The next bit you will study (if you take the next
  class). OO languages - Java, C, etc.
• Organize complex tasks in terms of services.
• A Program is viewed as an organization, or team.
  Each member of the team provides services that
  the others use.

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Vending machine

• Vending machine example
• Coin handler, does nothing more than take and
  give coins, keep balance
• Dispender, knows what is in machine, can dispense
• Selection button - knows when it is pressed, and
  can set display

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Functional Languages

• Based on expressions, function invocations, not
  variables.
• Computation is building a function (using
  existing functions), not incremental changes to
  state
• Much cleaner, but does it scale to large projects?

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Many more paradigms

• You will learn about many more paradigms in 381,
  elsewhere.
• Believe me, you have just scratched the surface !