The C arrays are tricky and they're described in every C tutorial. The other answers adresses mistakes / questions in comments, but none of them shows how it can be done:

struct BuzzNote {
  int note;
  int duration;
};

const BuzzNote melody[] = {
  {10, 200}, { 45, 300}, {90, 200}, // ...
};

void test(BuzzNote const * arr, size_t len) {
  for (size_t i = 0; i < len; ++i) {
    Serial.print(i);
    Serial.print(". ");
    Serial.print(arr[i].note);
    Serial.print(' ');
    Serial.println(arr[i].duration);
  } 
}

// using template for determining size of array (and as a bonus it won't work with plain pointers)
template<typename T, size_t size> 
size_t GetArrLength(T(&)[size]){return size;}
    
void setup() {
  Serial.begin(9600);
}

void loop() {
  test(melody, GetArrLength(melody));
  delay(10000);
}

I'm using template version of getting array length (it won't compile with pointers, as pointer isn't array).

And this version stores data in RAM (and waste it). If you don't have spare space in ram, you'll have to dig into PROGMEM variables/arrays. But it's the quest for another day :D

The C arrays are tricky and they're described in every C tutorial. The other answers adresses mistakes / questions in comments, but none of them shows how it can be done:

struct BuzzNote {
  int note;
  int duration;
};

const BuzzNote melody[] = {
  {10, 200}, { 45, 300}, {90, 200}, // ...
};

void test(BuzzNote const * arr, size_t len) {
  for (size_t i = 0; i < len; ++i) {
    Serial.print(i);
    Serial.print(". ");
    Serial.print(arr[i].note);
    Serial.print(' ');
    Serial.println(arr[i].duration);
  } 
}

// using template for determining size of array
// (and as a bonus it won't work with plain pointers)
template<typename T, size_t size> 
size_t GetArrLength(T(&)[size]){return size;}
    
void setup() {
  Serial.begin(9600);
}

void loop() {
  test(melody, GetArrLength(melody));
  delay(10000);
}

I'm using template version of getting array length (it won't compile with pointers, as pointer isn't array).

And this version stores data in RAM (and waste it). If you don't have spare space in ram, you'll have to dig into PROGMEM variables/arrays. But it's the quest for another day :D