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To have a clear understanding of computer science terms such as those that follow, we recommend lookingat Wikipedia
scope
within a program, it is a region where a variable can be accessed and its valuemodified
global scope
defined outside the methods setup() and draw(), the variable is visible andusable anywhere in the program
local scope
defined within a code block or a function, the variable takes values that arelocal to the block or function, and any values taken by a global variable having the same name are ignored.

Array declaration and allocation

int[] arrayDiInteri = new int[10];
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Programming structures

Conditional instructions

  • if: if (i == NMAX) { println("finished");} else {i++; }

Iterations

  • while: int i = 0; //integer counter while (i < 10) { //write numbers between 0 and 9 println("i = "+ i); i++; }
  • for: for (int i = 0; i < 10; i++) { //write numbers between 0 and 9 println("i = "+ i); }

Initializing a table of random numbers

int MAX = 10; float[] tabella = new float[MAX]; for (int i = 0; i < MAX; i++) tabella[i] = random(1); //random numbers between 0 and 1 println(tabella.length + " elements:"); println(tabella);
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Functions

Functions allow a modular approach to programming. In Processing, in the intermediate programming mode, we can define functions other than setup() and draw() , usable from within setup() and draw() .

Example of function

int raddoppia(int i) { return 2*i; }
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A function is characterized by the entities (with reference to the example ) :

  • return type ( int )
  • name ( raddoppia )
  • parameters ( i )
  • body ( return 2*i )

Objects and classes

A class is defined by a set of data and functions. An object is an instance of a class. Vice versa, a class is the abstractdescription of a set of objects.

For an introduction to the concepts of object and class see Objects and Classes .

Example of class

Dot myDot; void setup() { size(300,20); colorMode(RGB,255,255,255,100); color tempcolor = color(255,0,0); myDot = new Dot(tempcolor,0); } void draw() { background(0); myDot.draw(10); } class Dot { color colore; int posizione; //****CONSTRUCTOR*****// Dot(color c_, int xp) { colore = c_; posizione = xp; } void draw (int ypos) { rectMode(CENTER); fill(colore); rect(posizione,ypos,20,10); } }
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A class is characterized by the following entities (with reference to the example ) :

  • name ( Dot )
  • data ( colore, posizione )
  • constructor ( Dot() )
  • functions (or methods, draw() )

An object (instance of a class) is declared in the same way as we declare a variable, but we have to allocate a space for it(as we did for the arrays) by means of its constructor (with reference to the example ).

  • Declaration: ( Dot myDot; )
  • Allocation: ( myDot = new Dot(tempcolor,0) )
  • Use: ( myDot.draw(10); )

For a quick introduction to the Java syntax see Java Syntax Primer

With the following draw() method we want to paint the window background with a gray whose intensity depends on the horizontal position of themouse pointer. void draw() { background((mouseX/100)*255);} However, the code does not do what it is expected to do. Why?

The variable mouseX is of int type, and the division it is subject to is of the integer type. It is necessary to perform a type casting from int to float by means of the instruction (float)mouseX .

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Questions & Answers

A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
Aislinn Reply
cm
tijani
what is titration
John Reply
what is physics
Siyaka Reply
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Jude Reply
Can you compute that for me. Ty
Jude
what is the dimension formula of energy?
David Reply
what is viscosity?
David
what is inorganic
emma Reply
what is chemistry
Youesf Reply
what is inorganic
emma
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
Krampah Reply
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
Sahid Reply
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
Samuel Reply
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Joseph Reply
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
Ryan
what's motion
Maurice Reply
what are the types of wave
Maurice
answer
Magreth
progressive wave
Magreth
hello friend how are you
Muhammad Reply
fine, how about you?
Mohammed
hi
Mujahid
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
yasuo Reply
Who can show me the full solution in this problem?
Reofrir Reply
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Source:  OpenStax, Media processing in processing. OpenStax CNX. Nov 10, 2010 Download for free at http://cnx.org/content/col10268/1.14
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