Introduction to Programming

using the Processing language

Lecturer: Maarten Lamers of the Media Technology MSc program at Leiden University
Teaching assistant: Joris Slob
Course developed by Bas Haring (2004)
Alterations by Maarten Lamers (2005, 2006, 2007)

Introduction    Lecture I    Lecture II    Lecture III    Lecture IV    Lecture V    Lecture VI    Lecture VII    Fun

Programming concepts

 Functions (or methods)
Arguments
Return values
Scope of variables


Processing details

 Mouse interaction


Reserved words

 
void		abs()	max()		mouseX		mousePressed()
return()	sq()	min()		mouseY		mouseReleased()
strokeWeight()	sqrt()	ceil()		pmouseX		mouseMoved()
smooth()	pow()	floor()		pmouseY		mouseDragged()
random()	dist()
stroke()	fill()	point()

Question

 What will next program print? In other words, what is the value of i after func(i) has been executed? 
void setup() {
  int i = 7;
  func(i);
  println(i);
}

void func(int i) {
  i = 13;
}

Remark

 Clear layout of your code makes is much easier to read and understand the structure of your code. For example, indenting code that is 'captured' between the { and } brackets of a function definition makes it easier to see where the function starts and where it ends. Hint: pressing Ctrl-T in the Processing Environment indents your code for you. 

void setup() {
    // you can indent as many spaces as you wish
    int m = 28;
    func(m);
}