int ledO=2;
int ledB=3;
int ledV=4;
int ledJ=5;
int bouton=7;

int leds[] = {ledO, ledB, ledV, ledJ};
int numLed=4;

void setup() {
  // put your setup code here, to run once:
for (int i=0; i<numLed; i++){
  pinMode(leds[i],OUTPUT);
}
pinMode(bouton,INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
int etat_Bouton=digitalRead(7);
if(digitalRead(7)==1){
  for (int i=numLed-1;i>=0;i--){
    digitalWrite(leds[i],1);
    delay(250);
    digitalWrite(leds[i],0);
    delay(250);
  }
}
else {
  for (int i=0; i<numLed; i++){
    digitalWrite(leds[i],1);
    delay(250);
    digitalWrite(leds[i],0);
    delay(250);
  }
}
}