Functions

1. void setup(){}
2. void loop(){}
3. pinMode()
4. digitalWriter
5. analogWrite
6. digitalRead
7. analogRead
8. delay()

void setup(){}

this function work only once. the pinmodes are declared here

void loop(){}

this function loops just its name

pinMode()

this function is user to declare the pin number. As well as to declare whether the pin will be input or output.

e.g.

pinMode(pin-num, OUTPUT);

pinMode(pin-num, INPUT);