CS 111 - 9/6/12

Lab 1 is Due Tonight!!!!

Today: java Basics

Variables: name that is used to reference a memory location


Statement: variable declaration

Variable Type: the format that the information is stored

   int:   positive and negative whole numbers
   long:
   short:

   float:  positive and negative real numbers
   double:

   char:   stores an ASCII value

   String: sequence of char's 

   boolean:  a true or false value

 Syntax of a variable declaration statement


   <type> <identifier> ;

  Example:

   int value;
   double value2;
   String myName;

  indentifies must start with a letter and then can contain
     letters, digits and underscores

  Examples of Valid Identifies:
     number
     value37
     this_is_a_very_long_identifier 
     value73
     nubmer
     loopCounter
     dfgrrf56fdfgg4
     fred   

Assignment statement: stores information into a memory location  

 Syntax:

   <identifier> = <expression> ;

   The value respresented by the expression will be stored
     into the memory location associated with the identifier

  value = 10;

  value1 = value2 + value3;

  value1 = value2 * 5;

  value2 = (value1 + 7) * (value / 3);


 The following is a valid (and extremely useful) assignment
     BUT it is completely invalid in ALGEBRA
  value = value + 1;


Output Statement:  displays information to the user

   System.out.println ( <expression> ) ;

    The expression as converted to a string is displayed

    System.out.println ( value );

    System.out.println ( "Hello World!" );

    System.out.println ( "The identifier value contains: " + value );