blink led arduino

1void setup() {
2  LED_BUILTIN = 3; //or 13 
3  // initialize digital pin LED_BUILTIN as an output.
4  pinMode(LED_BUILTIN, OUTPUT); 
5}
6
7// the loop function runs over and over again forever
8void loop() {
9  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
10  delay(1000);                       // wait for a second
11  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
12  delay(1000);                       // wait for a second
13}

1void setup() {
2  // initialize digital pin LED_BUILTIN as an output.
3  pinMode(LED_BUILTIN, OUTPUT);
4}
5
6// the loop function runs over and over again forever
7void loop() {
8  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
9  delay(1000);                       // wait for a second
10  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
11  delay(1000);                       // wait for a second
12}

1void setup()
2{
3  pinMode(ledPin, OUTPUT);
4} 
5