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As you come in…. DOWNLOADS FOR TODAY : http://ce21sandiego.org/2013 CarGameTeacherStarter.a2w Online student textbook (at bottom of each page below ) Module 9.4 SpaceShipGame.a2w . Today’s plan. Functions
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As you come in… • DOWNLOADS FOR TODAY: • http://ce21sandiego.org/2013 • CarGameTeacherStarter.a2w • Online student textbook (at bottom of each page below) • Module 9.4 SpaceShipGame.a2w
Today’s plan • Functions • Compound booleanexpressions and if statements – can solve same problem multiple ways • Or – car magnet • And – space ship take off • Methods and Parameters
Functions: Calculate a Value and “Return” it. • Hides away complex calculation • When program executes that line/tile: change of control flow! • Jump to code/function that does the calculation • It “returns” the calculated value, which replaces the function call tile • Finally, that line/tile is executed
Examples you know (but can’t see/edit the code for) Object functions • Some calculate numbers • Distance To • Height • Some calculate boolean values • Is within X of Y • Is above
Examples you know (but can’t see/edit the code for) World functions • Some calculate numbers • Random number • Some calculate boolean values • Both a and b • Either a or b or both • a == b • a > b
Compound Boolean Expressions – ORCar Driving Game (watch video 9.2) • Modify: Car should only turn to head towards MAGNETS • One of the 4 magnets • Download from ce21sandiego.org/2013 • CarGameTeacherStater.a2w • Let’s create a function to hide away complex boolean expression
Create function: isMagnetReturns: boolean value • Create new World function • Choose returns boolean • Call it isMagnet (we often use “is” for boolean returning functions – Yes or No, true or false) • Drag boolean expression in if to clipboard • Go to isMagnet function definition replace “true” with expression from clipboard • BACK in my first method • Drag complex expression to trash • Replace (default) true with new isMagnet function (look under World, functions – it’s at top)
Compound Boolean Expressions – ORCar Driving Game (watch video 9.2) • In online text – used to show • Two ways you could make this if… • Compound boolean expression
Compound Boolean Expressions – ORCar Driving Game • Two ways if…
Compound Boolean Expressions – ORCar Driving Game • Two ways if… nested if
Compound Boolean Expressions – ANDSpaceship takes off • Space ship only takes off if all spheres are blue • Download from online textbook module 9.4 • SpaceShipGame.a2w (bottom of page) • Click on World object • Methods – edit Flip Switch • Build this if statement • When true – make dropShip object move up 30 meters
Compound Boolean Expressions – ANDSpaceship takes off • Two ways if…
Compound Boolean Expressions – ANDSpaceship takes off • Two ways if…
Coming Up… • Week 7: Methods, parameters, and events • Week 8: Lists