toggle 3 leds with one button

Using Arduino LEDs and Multiplexing
6

Try this:

int ledPin1 = 11;
int ledPin2 = 10;
int ledPin3 = 9;
int switchPin = 8;
int count = 0;
boolean lastButton;
boolean currentButton = false;
boolean ledOn = false;

void setup() {

  pinMode(switchPin, INPUT);
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
  count = 0;
}
//debounce function to stabilise the button
boolean debounce(boolean last)
{
  boolean current = digitalRead(switchPin);
  if (last != current)
  {
    delay(5);
    current = digitalRead(switchPin);
  }
  return current;  
}
void loop() {
  lastButton = currentButton;
  currentButton = debounce(lastButton);
  if (lastButton == false && currentButton == true)
  {
    if (count == 0) 
    { 
      count++;
      digitalWrite(ledPin1, HIGH);
      digitalWrite(ledPin2, LOW);
      digitalWrite(ledPin3, LOW); 
    }

    else if (count == 1)
    { 
      count++;
      digitalWrite(ledPin1, LOW); 
      digitalWrite(ledPin2, HIGH);
      digitalWrite(ledPin3, LOW);
    }

    else if (count == 2)
    { 
      count = 0;
      digitalWrite(ledPin1, LOW);
      digitalWrite(ledPin2, LOW);
      digitalWrite(ledPin3, HIGH); 
    }
  } 
}