music player

/*

*/
#define S0 4
#define S1 5
#define S2 6
#define S3 7
#define sensorOut 8
#define SPEAKER 9

const int buttonPin = 2;
const int switchPin = 3;

int buttonstate = 0;
int switchstate = 0;

int frequencies[20] = {0};
int red_frequency = 0;
int blue_frequency = 0;
int green_frequency = 0;
int sound_frequency = 0;

int frequency_calculation(int red_freq, int green_freq, int blue_freq) {
  return (red_freq + green_freq + blue_freq);
}
void setup() {
  pinMode(S0, OUTPUT);
  pinMode(S1, OUTPUT);
  pinMode(S2, OUTPUT);
  pinMode(S3, OUTPUT);
  pinMode(sensorOut, INPUT);
  pinMode(buttonPin, INPUT);
  pinMode(switchPin, INPUT);
}

void loop() {
  buttonState = digitalRead(buttonPin);
  switchState = digitalRead(swithPin);
  if (switchState == HIGH) {
    for (int i = 0; i < 20; i++) {
      tone(SPEAKER, frequencies[i], 100);
      delay(100);
    }
  } else {
      if (buttonState == HIGH) {
        for (int i = 0; i < 20; i++) {
        /*Getting the red frequency */
        digitalWrite(S2, LOW);
        digitalWrite(S3,LOW);
        red_frequency = pulseIn(sensorOut, LOW);

        /*Getting the green frequency */
        digitalWrite(S2,HIGH);
        digitalWrite(S3,HIGH);
        green_frequency = pulseIn(sensorOut, LOW);

        /*Getting the blue frequency */
        digitalWrite(S2,LOW);
        digitalWrite(S3,HIGH);
        blue_frequency = pulseIn(sensorOut, LOW);

        /*Getting the sound frequency and saving the value in the array*/
        sound_frequency = frequency_calculation(red_frequency, green_frequency, blue_frequency);
        tone(SPEAKER, sound_frequency, 100);
        frequencies[i] = sound_frequency;
        }
    } else {
      /*Getting the red frequency */
      digitalWrite(S2, LOW);
      digitalWrite(S3,LOW);
      red_frequency = pulseIn(sensorOut, LOW);

      /*Getting the green frequency */
      digitalWrite(S2,HIGH);
      digitalWrite(S3,HIGH);
      green_frequency = pulseIn(sensorOut, LOW);

      /*Getting the blue frequency */
      digitalWrite(S2,LOW);
      digitalWrite(S3,HIGH);
      blue_frequency = pulseIn(sensorOut, LOW);

      /*Playing the sound */
      sound_frequency = frequency_calculation(red_frequency, green_frequency, blue_frequency);
      tone(SPEAKER, sound_frequency, 100);
      delay(100);
    }
  }
}