Today I learned about variables in my lynda.com tutorial. According to Daniel Shiffman’s tutorial about object-oriented programming on Processing.org, variables are properties of an object. There are many different kinds of variables that you can create:
int = integer
float = decimal number
boolean = true/false
char = single character
byte = used with communication ports/Arduino
color = a color variable
Here is the code from the lynda.com tutorial I’ve been doing that includes information about these variables:
//lynda.com video on variables //int (integer) variable - whole number //32 bit... plus or minus 2 billion //declare the variable int x; //declared x x=10; //initialized x //println(x); println("x=" +x ); //float variable stands for floating point, has decimal places float e = 2.71828; println("e=" +e ); //boolean variable for true/false boolean switchVar = true; println("switchVar=" +switchVar ); switchVar = !switchVar; //! means this is not that println("switchVar=" +switchVar ); //Char variable (char means a single character) char charVar = 'V'; println("charVar=" + charVar ); //byte variable (goes down to -120 and up to 120...usually used in communication with serial ports //generally used with Arduino byte dozen = 12; println("The byte variable \"dozen\" is equal to: " + dozen ); // \means I'm done with my string, I don't want these quotes to print // color variable color cherryBlossomPink = #FFB7C5; background(cherryBlossomPink);
This code doesn’t produce any sketches except for a pink background as a result of the last variable listed.
Here also is a screenshot that displays variable scope; in other words you can have global variables which apply to all code, or local variables which apply only to one block of code. The lynda.com instructor also uses the command <pre>println</pre> which you can see at the bottom of this screenshot.
The result of this sketch? Nothing but a dark gray background.