int var = 1;      // variable to store the read value


void setup() {
  Serial.begin(115200);

  pinMode(2, OUTPUT); 
  pinMode(3, OUTPUT); 
  pinMode(4, OUTPUT); 
  pinMode(5, OUTPUT); 
  //pinMode(6, OUTPUT); 
  //pinMode(8, INPUT_PULLUP); 

}

void loop() {
 
 if (var==1) {
    ledPin2();
  }
  else if (var==2) {
    ledPin3();
  }
  else if (var==3) {
    ledPin4();
  }
  else if (var==4) {
    ledPin5();
 }

  if (var >= 4) {
    var = 1;
  }
  else {
    var = var + 1;
  }
  Serial.println(var);


}

//////////////////////////////

void ledPin2 () {
  digitalWrite(2, 1); // sets the LED on
  delay(500);  
  digitalWrite(2, 0); // sets the LED on
  delay(500);  
}

void ledPin3 () {
  digitalWrite(3, 1); // sets the LED on
  delay(500);  
  digitalWrite(3, 0); // sets the LED on
  delay(500);  
}

void ledPin4 () {
  digitalWrite(4, 1); // sets the LED on
  delay(500);  
  digitalWrite(4, 0); // sets the LED on
  delay(500);  
}

void ledPin5 () {
  digitalWrite(5, 1); // sets the LED on
  delay(500);  
  digitalWrite(5, 0); // sets the LED on
  delay(500);  
}