Loops & Arrays & Functions- Lets do this, some more. :|


///////////////////
/////////Loops
/////////////////
For loops

for( initialization; condition; increment step)

Example
for(var i = 15; i < 48; i = i + 1.1)


OR 
for(var i=0; i < 10; i++)

for(var i = 10; i >= 0; i--)

While the loop runs the loop variable changes and repeats the code.


///////////
While loops

Essentially an if statement that loops.

while(condition){
	//Executes if condition is true
	//If condition neer becomes false, loop destroys you all!
}

IT check the condition first, then decides to run or not.



Do While loops

Will do the loop code, condition or no condition, then check
Will run at least once.




Arrays!
Is a list of variables

Declaration: var lister = []

Usage:

lister[0] = "Whos"
lister[1] = "on"
lister.push("first");

Push just adds to the end, using specific index numbers (0,1, 2 etc) puts
data in specific spots.


Use a for loop to access the entire array.



var groc = []

groc[0] = 'eggs'			0 -> eggs
groc[1] = 'milk'			1 -> milk
groc[2] = 'other stuff'			2 -> other stuff
groc[4] = 'bread'			3 -> whatever black holes are made of
					4 -> bread

groc[1] = 'not milk'



groc.push("eggs");			0-> eggs
groc.push("milk");			1-> milk
groc.push("other stuff");		2-> other stuff
groc.push("bread"); 			3-> bread
groc.push("bread"); 			4-> bread


groc[3] = ""
use splice
groc.splice(3,1)

Splice Usage
array.splice(index, howMany);


Another useful thing.

.length

groc.length



for(var i=0; i < groc.length; i++){
	buy(groc[i]);

}


/////////////////////
///////	FUNCTIONS
///////////////////

Definition: function is a mini program inside the big program.

Functions can take in input, or not.
Functions can output a result, or not.


Example, no inputs, no outputs
function digHole(){
	universe.push("hole");

}

Worker, needed no information to work, and gave no report that job was done.


Upgrade, location required

Parameters= x and y

function digHole(x,y)
	universe[x][y] = "hole"
}


Upgrade, how did it go?

function digHole(x,y){
	var howDidItGo = "no idea";

	if(universe[x][y] == "diamond") howDidItGo = "poorly"
	else howDidItGo = "Super Easy"

	return howDidItGo;
}

usage:

var grandPlan = digHole(mx,my)

alert(grandPlan)



Lots of variables?

Local VS Global

Local are variables declared inside of smaller functions
howDidItGo is a local variable


Global are variable that are accessible by all functions, like mx & my




function print(message){
	papers.push(message);
}

print();


var gPapers = [];
var crap = [];


function getPapers(specific){
	var p; //A local variable, so you can have multiple getPapers running at the same time.


	//This part chooses the value to send back, in this case an entire array
	if(specific == "Good kind") p = gPapers
	else p = crap

	//Take the value and send it along
	return p
}

var evilPlan = getPapers("Good kind");
var incinerator = getPapers("stuf");

trash(incinerator)  /trash is some other made up function, just to show the super usage of getPapers;