• Create a new program

public class MyClassName
{
     // you can define a class variable here
     public static void main( )
     {
           // your statements will go here
           // your calls to method1 will have the form: method1()
     }
     public static void method1( )
     {
           // your statements will go here
     }
}

• create a variable
  • In Java: <type> <variable name> ;  example: int myIntVar;
  • declare with correct type: int, double, char, boolean, (not capitalized)
  • declare Object variables with types such as : String,   (capitalized)
• change variable contents:
  • In Java: <variable name> = <some expression>; example:  myIntVar = 5 ;.
  • Literal rules:
    • Strings should be in double quotes
    • char should be in single quotes
    • escape character \ makes the next character inside a string or char be interpreted differently
• Say something on the screen: 
  • In Java: System.out.println(<whatever you want to print> + <whatever you want to print> );
    
  • example: System.out.println("Hello, my name is " + myName + "My number is " + myNumber);
  • Remember: the semi-colon; capitalize System, use both parentheses;
    
  • Remember quotes around text and not around variable names
  • variations:   print
• Create (define) a method:
  
•     public static void methodname( )
       {
             // your statements will go here
       }
• Your method will only run if called.
  
• Your method returns to the spot where it left off when done.
  
• Invoke (call) a method:
• <method name> ( ) ; ex: methodname(); System.out.println("hello" ) ;
  
• Tools:
  • programming language: Java
  • programming tool: BlueJ
  • What you do: code (.java), compile (.class) and run (whatever method you want to run, usually main)
    
    
• Class and Method name (Identifier) rules:
  • An identifier must begin with a letter or an underscore _ or $
  • Java is case sensitive upper case (capital) or lower case letters are considered different characters. Average, average and AVERAGE are three different identifiers.
  • Numbers can also appear after the first character.
  • Identifiers can be as long as you want but names that are too long usually are too cumbersome.
  • Identifiers cannot be reserved words (special words like int, main, etc.)
  • By convention, names should begin with a lower case unless they are really representing something that wont ever change (CONSTANT) or a class 
  • By convention, a names whose value should never change should be all capitalized. (CONSTANT)

   

• Comments:
  • // -> comment line ex: // this is a comment
  • /* xxx */ comment between marks

 

• Flow Charts

• Charting a main routing and a method
• Symbols
  • Start / End Symbol (narrow oval)
  • Process Symbol (rectangle)
  • Method/Subroutine Symbol (rectangle with double bars on side)
  • Output (rectangle with edges curved to the outside)