4. Logika and, or

// C++ code
//

const int ledH = 10;
const int ledM = 11;
const int ledK = 12;
const int pbM = 5;
const int pbH = 6;

void setup()
{
  Serial.begin (9600);
  pinMode(ledH, OUTPUT);
  pinMode(ledM, OUTPUT);
  pinMode(ledK, OUTPUT);
  pinMode(pbM, INPUT);
  pinMode(pbH, INPUT);
}

void loop()
{
  if (digitalRead (pbM) == 0 && digitalRead (pbH) == 0){
    digitalWrite (ledH, HIGH);
    digitalWrite (ledM, HIGH);
    digitalWrite (ledK, HIGH);
  } 
  if (digitalRead (pbM) == 1 && digitalRead (pbH) == 0){
    digitalWrite (ledH, HIGH);
    digitalWrite (ledM, LOW);
    digitalWrite (ledK, LOW);
   } 
  if (digitalRead (pbM) == 0 && digitalRead (pbH) == 1){
    digitalWrite (ledH, LOW);
    digitalWrite (ledM, HIGH);
    digitalWrite (ledK, LOW);
  }
  if (digitalRead (pbM) == 1 && digitalRead (pbH) == 1){
    digitalWrite (ledH, HIGH);
    digitalWrite (ledM, HIGH);
    digitalWrite (ledK, LOW);
  }
}

Source : Youtube Life Tech