const int A = 7;
const int B = 6;
const int C = 12;
const int D = 11;
const int E = 10;
const int F = 9;
const int G = 8;
const int speaker = 13;
const int freqShift = 5;

const int freqA = 440;  //for A
const int freqB = 493;  //for B
const int freqC = 261;  //for C
const int freqD = 294;  //for D
const int freqE = 329;  //for E
const int freqF = 349;  //for F
const int freqG = 392;  //for G
int currentOctave = 0;
float multiplier;



void
  setup()
{
  pinMode(freqShift, INPUT);
  digitalWrite(freqShift, HIGH);

  pinMode(A, INPUT);
  digitalWrite(A,HIGH);

  pinMode(B, INPUT);
  digitalWrite(B,HIGH);

  pinMode(C, INPUT);
  digitalWrite(C,HIGH);

  pinMode(D, INPUT);
  digitalWrite(D,HIGH);
  
  pinMode(E, INPUT);
  digitalWrite(E,HIGH);
  
  pinMode(F, INPUT);
  digitalWrite(F,HIGH);
  
  pinMode(G, INPUT);
  digitalWrite(G,HIGH);
  


}

void loop()
{
 
  if (digitalRead(freqShift) == LOW) {
    currentOctave++;
    if (currentOctave > 4){
      currentOctave  = -3;
    }      
  }
  
  multiplier = pow(2, currentOctave);

  if(digitalRead(A)  == LOW)
  {
    tone(speaker, freqA * multiplier);
    delay(500);
    noTone(speaker);
  }

  if(digitalRead(B)  == LOW)
  {
    tone(speaker, freqB * multiplier);
    delay(500);
    noTone(speaker);
  }

  if(digitalRead(C)  == LOW)
  {
    tone(speaker, freqC * multiplier);
    delay(500);
    noTone(speaker);
  }

  if(digitalRead(D)  == LOW)
  {
    tone(speaker, freqD * multiplier);
    delay(500);
    noTone(speaker);
  }

  while(digitalRead(E)  == LOW)
  {
    tone(speaker, freqE * multiplier);
    delay(500);
    noTone(speaker);
  }

  while(digitalRead(F)  == LOW)
  {
    tone(speaker, freqF * multiplier);
    delay(500);
    noTone(speaker);
  }

  while(digitalRead(G)  == LOW)
  {
    tone(speaker, freqG * multiplier);
    delay(500);
    noTone(speaker);
  }
}