Can you run a function multiple times at the same time with Arduino Uno (c code)?

Question

I have eight LEDs, four red ones and four yellow ones. There is one button for both rows. When you push a button, a row of LEDs gets a pulse. That means they light up in a row in 0.1 second intervals. My question is now: Can I send a pulse while another one is still being processed? At the moment a function is called in which a for loop sets the state of the LEDs to HIGH and low, but I can not run it again, before it is finished.

void setup()
{
  pinMode(0, OUTPUT);
  pinMode(1, OUTPUT);
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(12, INPUT);
  pinMode(13, INPUT);
  Serial.begin(9600);
}
boolean wait(unsigned int j, unsigned int time) <-- test if 0.1 seconds have passed
{ 
  if (millis()>=time+j){
    return true;
  }
  else return false;
}
void pulse(int start)
{
    for(int j = start;j < start + 4;j++)
    {
      digitalWrite(j, HIGH);
      unsigned int time = millis();
     while(wait(100, time)==false){};
     digitalWrite(j, LOW);
    }
}
void loop()
{
  if (digitalRead(12) == HIGH)
  {
    Serial.println("yellow");
    pulse(2);                   <-- I have to wait for this function
  }
  if (digitalRead(11) == HIGH)
  {
    Serial.println("red");
    pulse(6);                   <-- I have to wait for this function
  }
}

Answer 1

This is how I would write the code for this project.

unsigned long yellowButtonPress = 0;
unsigned long yellowTimeElapsed = 0;
int yellowLED = 2

unsigned long redButtonPress = 0;
unsigned long redTimeElapsed = 0;
int redLED = 6

unsigned long MAX_Time = 400;

void setup(){
  //Setup the INPUT and OUTPUT pins
  for (int x=2; x<10; x++){
    pinMode(x, OUTPUT);
  }
    pinMode(12, INPUT);  //Yellow Button
    pinMode(13, INPUT);  //Red Button
}

void loop{
  yellowTimeElapsed = millis() - yellowButtonPress;
  redTimeElapsed = millis() - redButtonPress;

  //Check if yellow button has been pressed
  if(digitalRead(12) == HIGH && yellowTimeElapsed > MAX_Time){
    yellowButtonPress = millis();
  }

  //Check if red button has been pressed
  if(digitalRead(13) == HIGH && redTimeElapsed > MAX_Time){
    redButtonPress = millis();
  }

  //Identify which yellow LED needs to be on at this time
  if (yellowTimeElapsed > Max_Time){
    yellowLED=0; //This will turn off all yellow LEDs
  } else {
    yellowLED = map(yellowTimeElapsed, 0, MAX_Time, 2,5);
  }

  //Identify which red LED needs to be on at this time
  if (redTimeElapsed > Max_Time){
    redLED=0;  //This will turn off all red LEDs
  } else {
    redLED = map(redTimeElapsed, 0, MAX_Time, 6,9);
  }

  //Turn the yellow and/or red LEDs on and off
  for (int i = 2; i<10; i++){
    if (i == yellowLED || i == redLED){
      digitalWrite(i,HIGH);
    } else {
      digitalWrite(i,LOW);
    }
  }
}