// Program: 1B Ex5 Q1 Chan Tai Ming.ino

// Program: Ex5_Array.ino
/*
   Exercise 5 Array, string, and function
   Echo with some modifications
*/

char buf[100] = {0};  // this is an array
char inChar;
bool stringComplete = false;
int i = 0;

void setup()
{
  // Initialize serial and wait for port to open
  Serial.begin(115200);
  while (!Serial)
  {
    // Wait for serial port to connect, needed for native USB port only
  }
}

// ** IMPORTANT **
// MUST use buf[]
// CAN'T use functions like Serial.parseInt, Serial.readString

// Handle the UI (User Interface) like user prompt and error message
// User prompt: "Input a number"
// Error message: "Incorrect input"
// Add space between each set of input for better appearance (sort of UI)
// Refer to the example on the worksheet

void loop()
{
  int num;

  while (Serial.available())
  {
    inChar = (char)Serial.read();
    buf[i++] = inChar;

    if (inChar == '\n')   // change '\n' to '~' when using Tinkercad
    {
      // buf[i++] = inChar;  // last character is newline
      buf[i] = 0;         // string array should be terminated with a zero
      stringComplete = true;
    }
    else
    {
      // some actions after received
      // inChar = ConvertString(inChar);
      // buf[i++] = inChar;
    }
  }

  if (stringComplete)
  {
    Serial.print(buf);    // the printing of string will be stopped when zero is reached
    // Serial.println(i);

    if ((i == 2) && (isDigit(buf[0]))) {
      Serial.println("Good number");
      num = buf[0] - '0';
      PrintStars(num);
    } else {
      Serial.println("Not a good number");
    }

    // Write code to handle 2 digits
    // if ((i == 3)) && ...
    // Get the "num"ber
    // Print stars

    // PrintStars(24);

    stringComplete = false;
    i = 0;
  }
}

void PrintStars(int n) {
  // This loop can be implemented using while or do-while
  // How about j was initialized to 1?
  // for (int j = 1; j <= n; j++) {
  for (int j = 0; j < n; j++) {
    Serial.print("*");

    if ((j % 10) == 9) {
      Serial.println();
    }
  }
}