Functions

void setup() {

Serial.begin(9600);

pinMode(9,OUTPUT);

}

void loop() {

blinkLEDFast(); //calling the blinkLEDFast function

blinkLEDSlow(); //calling the blinkLEDSlow function

}

void blinkLEDFast(){ //declaring a function to blink led's fast

digitalWrite(9,HIGH);

delay(100);

digitalWrite(9,LOW);

delay(100);

digitalWrite(9,HIGH);

delay(100);

digitalWrite(9,LOW);

delay(100);

}

void blinkLEDSlow(){ //declaring a function to blink led's slowly

digitalWrite(9,HIGH);

delay(500);

digitalWrite(9,LOW);

delay(500);

digitalWrite(9,HIGH);

delay(500);

digitalWrite(9,LOW);

delay(500);

}

What is a function? How to declare and call functions?

A function declaration is as follows and happens after the void loop. If the function does not return a value it is declared with void type. If it returns a value then it has the variable type of the returned value, in this case int.

void functionName(parameters){

actions of function;

}

or

int functionName(parameters){

actions of function;

}

To call a function simply use the name of the function in a line of code. A function may or may not have parameters (inputs to the function). Above is an example of two functions without input parameters, below is an example with two input parameters l and w. The values of 5 and 6 are then passed into the function when it is called. You must call you functions within the loop.

void setup() {

Serial.begin(9600);

}

void loop() {

Serial.print("The area is ");

Serial.println(areaFunction(5,6));

}

int areaFunction (int w, int l){

int area = l * w;

return area;

}