//Student Name: Ho Kwok Fai
//Class: EG524403-1A
//Student Number: 230311289

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

// declare the function
void Printstar(int starNum);

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
  }

}

void loop()
{
  while (Serial.available())
  {
    inChar = (char)Serial.read();

    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
      buf[i++] = inChar;
    }
  }
  

    if (stringComplete)
    {
      Serial.print(buf);    // the printing of string will be stopped when zero is reached
      
      // Check if the input is a valid integer between 1 and 99
      if(isdigit(buf[0]) == true && buf[1] == '\n') // Convert the input string to an integer and pass it to the Printstar function
      {
        Printstar(buf[0]-'0');// Let the ASCII value of buf[0] change to Character
      }
      else if (isdigit(buf[0]) == true && isdigit(buf[1]) == true && (buf[2]) == '\n') // Convert the two-digit input string to an integer and pass it to the Printstar function
      {
        Printstar((buf[0]-'0')*10+(buf[1]-'0')); // Let the ASCII value of buf[0]&[1] change to Character
      }
      else
      {
        Serial.println("Incorrect input");
      }
      stringComplete = false;
      i = 0;
    }
}




// body of the function
void Printstar(int starNum) // Function to print stars based on the given number
{
  for(int j=1; j<=starNum; j++)
  {
    Serial.print('*');
    if(j%10 == 0 )
      Serial.print('\n'); // Print a newline character after every 10 stars
  }
  Serial.print('\n'); // Print an extra newline character at the end
}