1. Exam 2 Review

2. variable types boolean - true or false String - "hello" int - 14 double - 3.14159

3. instantiation crate a copy of a class for use by another class Utilities screen1 = new Utilities(); must use "new" can then use to call methods: screen1.writeToScreen( "hello", 10, 20 );

4. constructor see page 44 a method that has the same name as the class runs on instantiation of that class see ScreenWorld class

5. screen coordinates what do x and y mean where is (0,0) where is (0, 600) where is (600, 0) where is (600, 600) setLocation( x, y) method

6. GreenfootImage instantiate an object of the GreenfootImage class GreenfootImage myImage = new GreenfootImage( ); this.setImage( myImage ); in an Actor class myImage.drawString(....

7. Lab review the main point of each lab Lab 6 - screen writing Lab 5 - GreenfootImage, VirusPatrol, Virus Lab 4 - moving an Image, Hero( )

8. class / method/ variable definitions method definitions - public void act( ) class definitions - public class Hero extends Actor instance variable definitions - int x = 0; object definition (instantiation) - classname objectname = new classname( );

9. converting String s = "hello"; int i = 0; double x = 3.14159; ints to doubles x = (double) i ; doubles to ints i = (int) x; numbers to Strings s = String.valueOf( i ); s = String.valueOf( x );

10. writing to screen GreenfootImage myImage = new GreenfootImage( ); this.setImage( myImage ); myImage.setColor( Color.RED ); myImage.drawString("hello", 10, 10);

11. code int Looper = 0; while (Looper <= 100) { Looper++; // same as Looper = Looper+1; }

12. code if (x < 20 ) { y = 0; } else // i.e. if x >= 20 ! { y= 1; }

13. libraries greenfoot.*; GreenfootImage java.awt.*;Colors java.lang.Math;Math functions

14. methods with the same name? e.g. writeToScreen( String s, int x, int y ) writeToScreen( int i, int x, int y ) writeToScreen( double f, int x, int y ) writeToScreen( boolean t, int x, int y ) called OVERLOADING parameter list must be different

15. operators = assignment comparisons: = = equals ! = not equals (haven't used this yet) <less than <=less than or equal >greater than >=greater than or equal

16. operators && AND ||OR if ( (x = 10 )) if (( x==0 ) && ( y == 0))

17. if... else if ( x == 10 ) { // do this } else { // do THIS when x is not equal to 10 }

18. not on the test individual MATH functions plotting a curve