Adding an int to the word "led"

Projects Programming
1

Hello everyone!

I am doing something with a for loop and have several pins labeled led1, led2, led3 etc.

What I want to do to is to have a digitalWrite command inside a for loop so that I can have

digitalWrite(ledx, HIGH);

where x is the a number I have given in the for loop. So that if I gave the number 3, x would be 1,2,3 in sequence. This will then turn on led1, 2, and 3. The best way I can think to do this is to add the number x to the word led so that I get the name of my pin ie. "led1" or "led2". How can I do this?

Sorry if this is unclear, I've found this really hard to describe for some reason!

Thanks very much

2

Use arrays -

#define ARRAY_ENTRIES_COUNT(ARRAY)      (sizeof(ARRAY) / sizeof(ARRAY[0]))

const uint8_t   pinLED_1    = 3;
const uint8_t   pinLED_2    = 4;
const uint8_t   pinLED_3    = 5;

const uint8_t   arrayLEDS[] = { pinLED_1, pinLED_2, pinLED_3 };

void loop()
{
    ... some code ...

    for ( size_t i = 0; i < ARRAY_ENTRIES_COUNT(arrayLEDS); i++ )
    {
        digitalWrite(arrayLEDS[i], HIGH);
    }
    
    ... some code ...
}
3

As soon as you find yourself numbering variables (such as led1, led2, led3, ...), it is time to learn about arrays. lloyddean has shown one good way to use an array.

4

Thanks guys, I'll check out arrays :slight_smile: