uint64_t value creating from 8 bytes

Projects Programming
8

SHTIRLITZ:
Also my Serial.println() works correctly, and i can see a result (and it in decimal already).
But as you said, value uint64_t i can not convert to string and sent to TFT display....

char *toDec(uint64_t n) {
  static char buf[22];
  char *s = buf + 21;
  *s = '\0';
  if(n==0) {
    *--s = '0';
  }
  else {
    while(n) {
      *--s = '0' + n%10;
      n /= 10;
    }
  }
  return s;
}