How do I repeat a piece of code

Question

For a school assignment I need to make a LED blink on/of 3 times then stop. Now I have come up with the following code:

I think it's ''clean'' enough for what it has to do, but I have a feeling that here must be a easier way to make the LED blink 3 times.

Question is: Is there a way to reapeat the part of code 3 times without copy&pasting it?

Answer 1

Here you can use a loop. a classic for loop in C++ looks like this

for (int i = 0; i < n; i++)
{
    // content in between these brackets
}

where n is the amount of times you want to loop

you can also instantiate the i before the loop.

int i;
for (i = 0; i < n; i++)
{
    //content here
}

The code below should work. Toy around with it and see what you get.

int ledPin = 13;
int delayPeriod = 500;


void setup(){
    pinMode(ledPin, OUTPUT);

    for (int i = 0; i < 3; i++){
        digitalWrite(ledPin, HIGH);
        delay(delayPeriod);
        digitalWrite(ledPin, LOW);
        delay(delayPeriod);
    }

another approach you can do is using a while loop. These kinds of loops will loop until a given parameter has been met. In your case you want an LED to stop blinking after 3 times.

int start = 0;
int stop = 3;

while (start <= stop){
    //content here
}

While loops will continue to go as long as the parameter is true. This means something like while(1) will continue to run forever.

Answer 2

You could also look at optimising the 4 lines of code inside you loop:

const int ledPin = 13;
const int delayPeriod = 500;
const size_t count = 3;

void setup()
{
    pinMode(ledPin, OUTPUT);
    for (size_t loop = 0; loop < (count*2); ++loop) // size_t because variable is never negative.
    {  // Two time count, because you only have half the code
        digitalWrite(ledPin, (loop % 2)?HIGH:LOW);// Use Modulus
        delay(delayPeriod);
    }
}

Answer 3

Another way is to declare a function. This method will give you more chance of using it in various ways.

    int LED_PIN = 13;

    void flashing(size_t times=1) { // By default it will flash once, you can chance this into your desire
        int delayPeriod = 500;
        for (size_t loop = 0; loop < (times*2); ++loop) {
          digitalWrite(LED_PIN, (loop % 2)?HIGH:LOW);// Use Modulus
          delay(delayPeriod);
        } // Thanks to [Matt][1] and [Edgar Bonet][2] for their comments
    }

    void setup() {
        pinMode(ledPin, OUTPUT);
        flashing(3);
    }

    void loop() {
        // Do something here
    }