Computer Science

1
Computer Science

• Inside Class Methods

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Store Values

• Methods may need to store values
• Variables and Constants act as containers to hold
  these values

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Variables

• Variables are used to hold values
• Value may change

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Scope

• Every variable has a Scope
• tells where it is visible
• tells how long variable will hold its value

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Local Variables

• Local variables have Scope within the block they
  are created.
• A block is any code between opening and closing
  braces
• Variable will remain in scope within nested
  blocks
• Scope will extend throughout an objects life

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Local Variables

• Local Variables are not members of the class
• Do not mark local variables with access modifiers
  (public, private)
• Are local to the block in which they are created
• Not available to every method in the class
• Sole purpose of a variable is to help the method
  do its job

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Member Variables

• Member Variables are members of the class
• Value is available to any method, or member of
  that class

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Variables and Memory

• Computer memory is like a series of cubby holes,
  each having its own address.

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Variables and the Compiler

• Variable relay important information to the
  compiler
• What kind of object is in cubby
• Size of object
• Name of object
• Name is a synonym for the address
• Name used to access variable

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Initialization

• Initialization is the process of declaring a
  variable and assigning it a value
• Example
• int x5
• Int is the data type
• x is the name
• 5 is the assigned value

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Initialize More Than One

• Using comas, you can declare and initialize more
  than one variable at a time

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Dont Become Confused

• Assignment Operator ()
• Assigns a value
• X5
• Equality operator ()
• Equality operator test whether value is equal to
  x
• X5