// Program: 1X Ex5 Q1 Chan Tai Ming_2.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;

// declare the function
// char ConvertString(char);

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
  // }
  Serial.println("Input a number:");
}

void loop()
{
  int num;
  bool goodString = true;

  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

    // Define the actions
    // Serial.println(i);

    if ((i < 2) || (i > 3)) {
      goodString = false;
    } else {
      for (int j = 0; j < i - 1; j++) {
        if (!isDigit(buf[j])) {
          goodString = false;
        }
      }
    }

    if (goodString) {
      if (i == 2) {
        num = buf[0] - '0';
      } else {
        num = (buf[0] - '0') * 10 + (buf[1] - '0');
      }
      // Serial.println("Good");
      PrintStars(num);
    } else {
      Serial.println("Incorrect input");
    }

    Serial.println();
    Serial.println("Input a number:");
    
    stringComplete = false;
    i = 0;
  }
}

// body of the function
// char ConvertString(char x)
// {
//   if (isUpperCase(x))
//     return (toLowerCase(x));
//   else if (isLowerCase(x))
//     return (toUpperCase(x));
//   else
//     return (x);
// }

void PrintStars(int n) {
  for (int i = 1; i <= n; i++) {
    Serial.print("*");
    if (!(i % 10)) {
      Serial.println();
    }
  }
  
  if (n % 10) {
    Serial.println();
  }
}