MzTEK Programming - Part 2

REVIEW LAST WEEK

Think of idea

Break down problem into tiny steps

Write code for one step

Run program

Code You’ve Written

Instructions for Computer?

Executable Program (e.g. .exe or .app)

Interactive Development

Environment (IDE)

Compiler +

Linker +

Loader

int x;int y;int width;int height;

size(200, 200);

x = 150;y = 100;width = 90;height = 80;

ellipse(x, y, width, height);


size(200, 200);

x = 150;y = 100;width = 90;height = 80;


ingredients or variables


size(200, 200);

x = 150;y = 100;width = 90;height = 80;



directions or algorithm


size(200, 200);

x = 150;y = 100;width = 90;height = 80;




data type


size(200, 200);

x = 150;y = 100;width = 90;height = 80;




data type variable name

DECLARATION VS INITIALISATIONAs in a recipe, ingredients need to be listed at the top so you know what to buy.

In code, it’s so the compiler knows how much memory to reserve. This is called declaring.



int myInt;

Reserve space for an int



We don’t have to know what value will be stored in myInt right away.

We can choose a value later. This is called initialising.

int myInt;




We don’t have to know what value will be stored in myInt right away.

We can choose a value later. This is called initialising.

int myInt;


myInt = 15;

Store the value 15 in the space reserved for myInt

15

Need to declare before or at the same time as initialisation.


myInt = 3;int myInt;



int myInt; myInt = 3;




Can’t use a variable before it is initialised.




int myInt;myInt = myInt + 7;





int myInt = 3;myInt = myInt + 7;

int myInt;myInt = myInt + 7;


TO CREATE A VARIABLE1. Decide what the data type should be. Usually the main

decisions are between int, float and char.

floatintchar



floatintchar

to create a float type



floatintchar


to create an int type



floatintchar



to create a char type



2. Decide on a name for your variable. Remember the rules.

floatintchar







floatintchar




float scale;int redValue;char finalMark;




floatintchar





you get to choose the name




3. If you already know what the value of that variable is, then go ahead and set the value.

floatintchar










floatintchar





float scale = 0.5;int redValue = 199;char finalMark = ‘B’;






floatintchar





float scale = 0.5;int redValue = 199;char finalMark = ‘B’;

if you don’t know the value yet, stop at step 2. but remember to end

each line with a ;


EXERCISE

In Processing, draw a purple quadrilateral using the quad( ) function.

quad(int x1, int y1, int x2, int y2, int x3, int y3, int x4, int y4)

Use variables to represent corner of the quadrilateral.

ARRAYS

int x0 = 20;int y0 = 20;int x1 = 30;int y1 = 50;int x2 = 150;int y2 = 50;int x3 = 160;int y3 = 20;

size(200, 200);quad(x0, y0, x1, y1, x2, y2, x3, y3);



this is a pain to keep track of



this is a pain to keep track of

Wouldn’t it be easier to just have two lists, so only two variable names: “x” and “y”?

X

0.) 20

1.) 30

2.)150

3.)160

Y

0.) 20

1.) 50

2.) 50

3.) 20

What if had a list called X

And a list called Y

X

0.) 20

1.) 30

2.)150

3.)160

Y

0.) 20

1.) 50

2.) 50

3.) 20


And a list called Y

So if we just want the number at 2.) in the X list, we’d type

x[2]

X

0.) 20

1.) 30

2.)150

3.)160

Y

0.) 20

1.) 50

2.) 50

3.) 20


And a list called Y

So if we just want the number at 2.) in the X list, we’d type

x[2]

That’s all an array is:a list of things, where we don’t have to

name each thing, just the list.

To create a new list (to declare it):

int[] x = new int[4];



what kind of things are in the list? i.e. how much space needs to be

reserved for each item





[ ] means the data type is an array



what is the name of the list?








reserved for each item how long will the list be?


To initialise a new list :

x[0] = 20;x[1] = 30;x[2] = 150;x[3] = 160;


x[0] = 20;x[1] = 30;x[2] = 150;x[3] = 160;

what list are you referring to?


x[0] = 20;x[1] = 30;x[2] = 150;x[3] = 160;

which item from the list?



x[0] = 20;x[1] = 30;x[2] = 150;x[3] = 160;

which item from the list?


what is the value of that item?


x[0]

x[1]

x[2]

x[3]




x[0]

x[1]

x[2]

x[3]

the length of the array and the data type determine

how much memory is used

You can declare and initialise a new list at the same time :

int[] x = {20, 30, 150, 160};


int[] x = {20, 30, 150, 160};




int[] x = {20, 30, 150, 160};

what is the value of each item?





In Processing, rewrite this code so that it uses two arrays.

EXERCISE



CONTROL STRUCTURES

1. Heat the oil in a large, heavy-based saucepan and fry the bacon until golden over a medium heat. Add the onions and garlic, frying until softened. Increase the heat and add the minced beef. Fry it until it has browned, breaking down any chunks of meat with a wooden spoon. Pour in the wine and boil until it has reduced in volume by about a third. Reduce the temperature and stir in the tomatoes, drained mushrooms, bay leaves, oregano, thyme and balsamic vinegar.

2. Either blitz the sun-dried tomatoes in a small blender with a little of the oil to loosen, or just finely chop before adding to the pan. Season well with salt and pepper. Cover with a lid and simmer the Bolognese sauce over a gentle heat for 1-1½ hours until it's rich and thickened, stirring occasionally. At the end of the cooking time, stir in the basil and add any extra seasoning if necessary.

3. Remove from the heat to 'settle' while you cook the spaghetti in plenty of boiling salted water (for the time stated on the packet). Drain and divide between warmed plates. Scatter a little parmesan over the spaghetti before adding a good ladleful of the Bolognese sauce, finishing with a scattering of more cheese and a twist of blackhttp://www.bbc.co.uk/food/recipes/spaghettibolognese_67868

2 tbsp olive oil or sun-dried tomato oil from the jar6 rashers of smoked streaky bacon, chopped2 large onions, chopped3 garlic cloves, crushed1kg/2¼lb lean minced beef2 large glasses of red wine2x400g cans chopped tomatoes1x290g jar antipasti marinated mushrooms, drained2 fresh or dried bay leaves

1 tsp dried oregano or a small handful of fresh leaves, chopped1 tsp dried thyme or a small handful of fresh leaves, choppedDrizzle balsamic vinegar12-14 sun-dried tomato halves, in oilSalt and freshly ground black pepperA good handful of fresh basil leaves, torn into small pieces800g-1kg/1¾-2¼lb dried spaghettiLots of freshly grated parmesan, to serve

http://www.bbc.co.uk/food/olive_oil

http://www.bbc.co.uk/food/olive_oil

http://www.bbc.co.uk/food/bacon

http://www.bbc.co.uk/food/bacon

http://www.bbc.co.uk/food/onion

http://www.bbc.co.uk/food/onion

http://www.bbc.co.uk/food/garlic

http://www.bbc.co.uk/food/garlic

http://www.bbc.co.uk/food/red_wine

http://www.bbc.co.uk/food/red_wine

http://www.bbc.co.uk/food/chopped_tomatoes

http://www.bbc.co.uk/food/chopped_tomatoes

http://www.bbc.co.uk/food/mushroom

http://www.bbc.co.uk/food/mushroom

http://www.bbc.co.uk/food/oregano

http://www.bbc.co.uk/food/oregano

http://www.bbc.co.uk/food/thyme

http://www.bbc.co.uk/food/thyme

http://www.bbc.co.uk/food/balsamic_vinegar

http://www.bbc.co.uk/food/balsamic_vinegar

http://www.bbc.co.uk/food/tomato

http://www.bbc.co.uk/food/tomato

http://www.bbc.co.uk/food/black_pepper

http://www.bbc.co.uk/food/black_pepper

http://www.bbc.co.uk/food/basil

http://www.bbc.co.uk/food/basil

http://www.bbc.co.uk/food/spaghetti

http://www.bbc.co.uk/food/spaghetti

http://www.bbc.co.uk/food/parmesan_cheese

http://www.bbc.co.uk/food/parmesan_cheese






We’ve covered how to create ingredients or variables.






We’ve covered how to create ingredients or variables.

Now onto the basics of how to use those variables.

HOW TO MAKE A DECISION

HOW TO MAKE A DECISIONOnce we have some variables, we want to do things with those variables.

The most basic step is to compare those variables to something else.

This is done with comparators - questions that can be answered yes or no (or true or false).




<




<less than




7 4<less than

FALSE




7 4<less than




>




>greater than




7 4>greater than

TRUE




7 4>greater than

OTHER COMPARISONS

>=

<=

==

!=

greater than or equal to

less than or equal to

equal to

not equal to

All of these result in true or false.

if ( ) {

}else {

}

if ( ) {

}else {

}

put in a comparison statement (like < or >)

if ( ) {

}else {

}


what to do if our comparison statement is true

if ( ) {

}else {

}



what to do if our comparison statement is false

if ( ) {

}else {

}

we don’t have to always have an else

statement, sometimes you only care if the statement is true



what to do if our comparison statement is false

If something is true, do an action.

If something isn’t true, instead do a different action.




If the potatoes are too lumpy, keep mashing.




If the potatoes are not too lumpy, stop mashing.




If the potatoes are not too lumpy, stop mashing.

We don’t have to test this twice. We know if the potatoes are either too lumpy or not too

lumpy.

When graphing information, we are used to numbers

A NOTE ON AXES


increasing as we move right

A NOTE ON AXES


and increasing as we move up

increasing as we move right

A NOTE ON AXES

A NOTE ON AXES

This is different to how numbers work with programming graphics.

A NOTE ON AXES


Numbers start in the upper left corner at the

origin (0, 0)

A NOTE ON AXES


and increase as we move right


origin (0, 0)

A NOTE ON AXES


and increase as we move down

and increase as we move right


origin (0, 0)

EXERCISECreate a Processing sketch which draws a green circle if the mouse is in the top half of the window and changes the circle’s colour to red if the mouse in the bottom half of the window. Start with the code below.

void setup() {// create the windowsize(400, 400);

}

void draw() {// set the colourfill(10, 10, 255);

// draw the circleellipse(mouseX, mouseY, 100, 100);

}

What if we want to use multiple if statements?

int counter;// some other code...if (counter < 10) {if (counter > 0 ) {counter++;

}}



}}

If counter is less than 10 and greater than 0, then increase counter by 1.



}}


counter is only increased if both if statements are true.



}}


These are called nested if statements, because one is inside the { } of the other.

counter is only increased if both if statements are true.

int counter;// some other code...if (counter > 10) {counter = 0;

}if (counter < 0 ) {}counter = 0;

}




}

If counter is greater than 10 or less than 0, then reset counter to 0.




}

If counter is greater than 10 or less than 0, then reset counter to 0.

counter is reset if either if

statements are true.


BOOLEAN OPERATOR OR

ORTrue False

TrueFalse

True True

False False

OR

OR

OR

is

is

is

is

BOOLEAN OPERATOR OR

ORTrue False

TrueFalse

True

True True

False False

OR

OR

OR

is

is

is

is

BOOLEAN OPERATOR OR

ORTrue False

TrueFalse

True

True True

False False

OR

OR

OR

is

is

is

is

True

BOOLEAN OPERATOR OR

ORTrue False

TrueFalse

True

True True

False False

OR

OR

OR

is

is

is

is

True

True

BOOLEAN OPERATOR OR

ORTrue False

TrueFalse

True

False

True True

False False

OR

OR

OR

is

is

is

is

True

True

BOOLEAN OPERATOR OR

ORTrue False

TrueFalse

True

False

True True

False False

OR

OR

OR

is

is

is

is

True

True

When using OR in code, type ||

BOOLEAN OPERATOR AND

ANDTrue False

TrueFalse

True True

False False

AND

AND

AND

is

is

is

is


ANDTrue False

TrueFalse

True True

False False

AND

AND

AND

is

is

is

is

False

False


ANDTrue False

TrueFalse

True True

False False

AND

AND

AND

is

is

is

is

False

False


ANDTrue False

TrueFalse

True True

False False

AND

AND

AND

is

is

is

is

True

False

False


ANDTrue False

TrueFalse

False

True True

False False

AND

AND

AND

is

is

is

is

True

False

False


ANDTrue False

TrueFalse

False

True True

False False

AND

AND

AND

is

is

is

is

True

When using OR in code, type &&

False

BOOLEAN OPERATOR NOT

NOT True

FalseNOT

is

is


NOT True

FalseNOT

Falseis

is


NOT True

FalseNOT

False

True

is

is


NOT True

FalseNOT

False

True

is

is

When using NOT in code, type !

EXERCISEModify your Processing sketch which draws a green circle if the mouse is in the top half of the window and changes the circle’s colour to red if the mouse in the bottom half of the window.

Now using the AND statement, draw

• a green circle in the upper left quadrant of the window,

• a blue circle in the upper right quadrant,

• a red circle in the lower left quadrant,

• and a yellow circle in the lower right quadrant.

LOOPS

There are two ways to repeat something:

1. Do this N number of times.

2. Keep doing this until something else happens.

LOOPS




Repeat this event in the calendar this

many times.

LOOPS




Repeat this event in the calendar this

many times.

Repeat this event in the calendar until a certain

date occurs.

DO THIS N TIMES

int i;for(i=0; i<4; i++) {

}

DO THIS N TIMES

int i;for(i=0; i<4; i++) {

}

start with a number, in this case 0

DO THIS N TIMES

int i;for(i=0; i<4; i++) {

}


if this statement is true

DO THIS N TIMES

int i;for(i=0; i<4; i++) {

}



then do whatever is written here

DO THIS N TIMES

int i;for(i=0; i<4; i++) {

}



when you’ve done what’s in the { } once, do this, in this case add make i equal to its current value plus 1


DO THIS N TIMES

int i;for(i=0; i<4; i++) {

}



when you’ve done what’s in the { } once, do this, in this case add make i equal to its current value plus 1


go back to see if the middle statement is still

true

KEEP DOING THIS UNTIL SOMETHING ELSE HAPPENS

while ( ) {

}


while ( ) {

}

if the statement here is true


while ( ) {

}


then do what is between { } once


while ( ) {

}


then do what is between { } once

then repeat by checking the statement again

EXERCISEWrite out each iteration of these loops and what the variables equal at the end of each loop.

int i;int j = 15;

for (i=0; i<12; i++) {j = j * 2 - i;

}

int k = 100;

while ( k > 0 ) {k = k -10;

}

MzTEK Programming - Part 2

Education

Transcript of MzTEK Programming - Part 2