/* Adafruit Arduino - Lesson 3. RGB LED */

int redPin = 11; int greenPin = 10; int bluePin = 9;

//uncomment this line if using a Common Anode LED //#define COMMON_ANODE

void setup() {
pinMode(redPin, OUTPUT);
pinMode(greenPin, OUTPUT); pinMode(bluePin, OUTPUT); }

void loop() {
setColor(255, 0, 0); // red
delay(1000);
setColor(0, 255, 0); // green
delay(1000);
setColor(0, 0, 255); // blue
delay(1000);
setColor(255, 255, 0); // yellow
delay(1000);
setColor(80, 0, 80); // purple
delay(1000);
setColor(0, 255, 255); // aqua delay(1000); }

void setColor(int red, int green, int blue) {
#ifdef COMMON_ANODE red = 255 - red; green = 255 - green; blue = 255 - blue;
#endif
analogWrite(redPin, red);
analogWrite(greenPin, green);
analogWrite(bluePin, blue); }

In this code, why were they able to carry out setColor before expanding upon what it means later through "void setColor(int red, int green, int blue)"? Should that portion of the code come earlier or does it matter? Also I don't quite understand how the definition of the colors red, green, and blue were defined towards the bottom. I know what 255 would indicate maximum brightness, but why do you have to subtract the color from 255? Any help would be much appreciated.

/* Adafruit Arduino - Lesson 3. RGB LED
*/

int redPin = 11;
int greenPin = 10; 
int bluePin = 9;
 
 //uncomment this line if using a Common Anode LED //#define
 COMMON_ANODE
 
void setup() {   
pinMode(redPin, OUTPUT);   
pinMode(greenPin, OUTPUT);
pinMode(bluePin, OUTPUT);   }
 
void loop() {  
  setColor(255, 0, 0);  // red   
  delay(1000);  
  setColor(0, 255, 0);  // green  
  delay(1000);  
  setColor(0, 0, 255); // blue   
  delay(1000);   
  setColor(255, 255, 0);  // yellow  
  delay(1000);    
  setColor(80, 0, 80);  // purple   
  delay(1000);  
  setColor(0, 255, 255);  // aqua 
  delay(1000); }
 
void setColor(int red, int green, int blue) {   
#ifdef COMMON_ANODE
     red = 255 - red;
     green = 255 - green;
     blue = 255 - blue;  
#endif   
  analogWrite(redPin, red);   
  analogWrite(greenPin, green);  
  analogWrite(bluePin, blue);   }

In this code, why were they able to carry out setColor before expanding upon what it means later through void setColor(int red, int green, int blue)? Should that portion of the code come earlier or does it matter? Also I don't quite understand how the definition of the colors red, green, and blue were defined towards the bottom. I know what 255 would indicate maximum brightness, but why do you have to subtract the color from 255? Any help would be much appreciated.