Anchors Aweigh

/*
 * Based on the sketch found at https://gist.github.com/elubow/7844436.
 * The original sketch plays "Jingle Bells" repeatedly on pin 5.
 * This version plays "Anchors Aweigh" once on pin 13.
 * No licensing information was found for the original sketch. This version
 * (or at least the modifications, if the original is under any license) is
 * Public Domain.
 * 
 * Notes:
 *  Changed song to "Anchors Aweigh"
 *  Added line to prevent repeated playing
 *  Changed beats[] from int to float
 *  Added notes :
 *    D above high C* : D
 *    E above high C* : E
 *    F Sharp         : F
 --------------
      * Note: This is high C, not "high seas." Get it? Navy?
 */
int speakerPin = 13;
int length = 51;
char notes[] = "cegaeaCDgCaCagabCFadCbgfdcegaeaCDgCaCagabcEgFgDgfgC";
float beats[] = { 2, 1, 1,   1.5, 0.5, 2,  2, 1, 1,   4,  2, 1, 1,   1, 1, 1, 1,  1, 1, 1, 1,  1, 1, 1, 1,  2, 1, 1,    1.5, 0.5, 2,    2, 1, 1,   4,  2, 1, 1,   1, 1, 1, 1, .75, .25, .5, .125, .75, .25, .5, .5,  4};

int tempo = 300;
void playTone(int tone, int duration) {
  for (long i = 0; i < duration * 1000L; i += tone * 2) {
    digitalWrite(speakerPin, HIGH);
    delayMicroseconds(tone);
    digitalWrite(speakerPin, LOW);
    delayMicroseconds(tone);
  }
}
void playNote(char note, int duration) {
  char names[] = { 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'C', 'D', 'E', 'F' };
  int tones[] = { 1915, 1700, 1519, 1432, 1275, 1136, 1014, 956, 901, 849, 1390 };

  // play the tone corresponding to the note name
  for (int i = 0; i < 11; i++) {
    if (names[i] == note) {
      playTone(tones[i], duration);
    }
  }
}
void setup() {
  pinMode(speakerPin, OUTPUT);
}
void loop() {
  for (int i = 0; i < length; i++) {
    if (notes[i] == ' ') {
      delay(beats[i] * tempo); // rest
    } else {
      playNote(notes[i], beats[i] * tempo);
    }

    // pause between notes
    delay(tempo / 2);
  }
  while (true) {}
}