Skeletons in Your Closet

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Skeletons in Your Closet
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Overview

• Documenting Your Programs
• The Application Skeleton
• Printing to the screen
• Getting input from the user
• Your first C Program
• Knowing when to compile

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The Skeleton

• include ltiostreamgt
• using namespace std
• void main ( )
• // Go ahead and memorize this.
• // It has to be there!
• // Note this should go in a .cpp file

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Documenting Your Programs

• This is called commenting, and the computer
  ignores this when compiling.
• Theres 2 ways to do it in C!
• // This is for a single line comment.
• / This is for a paragraph of comments
• and can go on and on. It doesnt matter
• until you see the /

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Printing to the Screen

• Use cout to do this (pronounced see-out)
• cout can print out just about anything
• Variables of most data types
• Multiple things at once
• Special characters like \n (newline), \a
  (alert), etc..
• Print multiple things with additional ltlts
• Print out endl to drop to next line
• Example
• cout ltlt Tori Spelling scares me
• cout ltlt Hello ltlt world! ltlt endl

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Getting Input from the User

• Use cin (pronounced see-in)
• Read into variables (later)
• Example
• // Declare a variable
• int myInt
• // Load it with information from the keyboard
• cin gtgt myInt
• // Print it out
• cout ltlt myInt is ltlt myInt ltlt endl

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Your First C Program

• include ltiostreamgt
• using namespace std
• void main ( )
• cout ltlt Hello World ltlt endl
• // Note yes, this should be put into a .cpp file

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Rules about Syntax

• Where do the s go?
• Semicolons come after single statements
• Similar to a period at the end of a sentence
• Where do the and go?
• Creates a block of text for multiple single
  statements
• tells the computer to begin a section
• tells the computer to end a section
• Can be nested (or inside of each other)
• Lets go back to our first c program

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Your First C Program
include ltiostreamgt using namespace std void
main ( ) cout ltlt Hello World ltlt endl
Begin the main
End the main
End a single statement
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Compiling Your Program

• Youll use one of two things
• The command-line g (on Unix)
• Your IDE (like Visual C)
• When you compile, youll have one of two things
  happen
• It compiles
• It doesnt
• If it doesnt compile, you have syntax errors

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Knowing When to Compile

• As a rule, the less comfortable you are, the more
  you should compile
• This isolates the errors
• As a rule, compile
• After you type in the skeleton
• After every 5 or 10 lines of new code
• Dont become dependent on the compiler!

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Summary

• KNOW the skeleton
• Basis of every program you write
• Know the s and s
• Document your programs thoroughly
• Cin reads from the keyboard
• Cout prints to the screen
• Compile often to isolate errors

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