#define C 261
#define D 293
#define E 329
#define F 349
#define G 392
#define A 440
#define H 494
int but;
void setup()
{
  Serial.begin(9600);
  for(int i = 7;i<14;i++)
  {
    pinMode(i,INPUT);
  }
  pinMode(2,OUTPUT);
}

void loop()
{
  digitalRead(7) == 1? but = 7 : false;
  digitalRead(8) == 1? but = 8 : false;
  digitalRead(9) == 1? but = 9 : false;
  digitalRead(10) == 1? but = 10 : false;
  digitalRead(11) == 1? but = 11 : false;
  digitalRead(12) == 1? but = 12 : false;
  digitalRead(13) == 1? but = 12 : false;

  switch(but)
  {
    case 7:
        tone(2,H,200);
    break;
    case 8:
        tone(2,A,200);
    break;
    case 9:
        tone(2,G,200);
    break;
    case 10:
        tone(2,F,200);
    break;
    case 11:
        tone(2,E,200);
    break;
    case 12:
        tone(2,D,200);
    break;
    case 13:
        tone(2,C,200);
    break;
  }
  but = 0;
}