Trying to retrieve a number in string and use it as index for an array of pinled

Projects Programming
1

Hi! First of all thanks in advance for reading.
I'm taking first steps with Arduino. I'm trying to make a Simon Game (Please if it this already exist don't send me a link. i'm tryint to do it by my self).

To add new pin colors after succesful tries i've created a String to enlarge the led order. I choose string type because .charAt() function.

This is the relevant part of the code

int led[] = {9, 8, 7, 6}; 
int buttonPressed[4];
String randomStep; //string para manejar los random
unsigned int lastStep = 0;

void setup() {
   Serial.begin(9600);
  //Setup the LED :
  for (int i = 0; i < (sizeof(led)/sizeof(int)); i++) {
    pinMode(led[i], OUTPUT);
  }
  randomSeed(analogRead(0));
}

void loop() {
  if (randomStep.length() == 0) {
      // Startup Code //
  }
  if (randomStep.length() != lastStep) {

      // [+++ here goes code with buttons ++++ Succesful attemp would increment lastStep
          lastStep++;
          
      }
  }
 

 } else { 
      //So here are my issues!!!
      randomStep = randomStep + String(random(0,4));
      for (int i=0; i < randomStep.length(); i++) {
        int currentLed;
        currentLed = (int)randomStep.charAt(i);
        Serial.print(led[(char)currentLed]);
        //if I send the variable to Serial it shows me 0, 1 2 or 3 which are the possible numbers
        // but when I'm trying to get the ledPIN from led[] array, serial monitor shows me 14891 or 29281 (depending of value) 
       //I tried with (int) (long)
       // using atoi always give me 0.
        digitalWrite(led[currentLed],HIGH);
        delay(500);
        digitalWrite(led[currentLed],LOW);
        delay(500);
      }
  
 }

}

What do I need to do to get the correct type to pass it to array as an array Index? Is there a better way to do this?

Please forgive my writing.
I'm not very sure if i'm explaining myself. English is not easy for me.

Regards
Rodrigo de los Santos

2

Finally i've managed throug a switch/case... I don't know if i'm reinventing the wheel with this. In my country it could be called "Una Grasada" but it worked for me.

...
        int currentLed;
        currentLed = randomStep.charAt(i);
        int selectedLed;
          switch (currentLed) {
            case 48:
            selectedLed = 0;
            break;
            case 49:
            selectedLed = 1;
            break;
            case 50:
            selectedLed = 2;
            break;
            case 51:
            selectedLed = 3;
            break;
            default:
          }

        digitalWrite(led[selectedLed],HIGH);
        delay(500);
        digitalWrite(led[selectedLed],LOW);
        delay(500);
...

I suppose there are another, more easy to do.
Regards

3

I suppose there are another, more easy to do.

Leaving aside the unnecessary use of Strings for now, in your switch/case do you see the consistent relationship between the value of currentLed and selectedLed ? Subtract 48 from currentLed and what number do you get ?

4 
int currentLed= randomStep.charAt(i);
int selectedLed = currentLed - '0';