// 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; //initializes it with the value 'false'
bool invalidInput = false; //initializes it with the value 'false'
int inputNumber1 = 0;
int inputNumber0 = 0;
int i = 0;

char CheckString(char); // declare the function

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 (!isDigit(inChar))
        {
        invalidInput = true;
        }
    }
  }

  if (stringComplete)
  {
     // check \n location
        if ( i > 3 ) //When the value exceeds ten digits, will show incorrect input
    {
        invalidInput = true;
    }
        if (invalidInput){
        Serial.print(buf); // the printing of string will be stopped when zero is reached
        Serial.print("Incorrect input");
        Serial.print("\n");
        invalidInput = false;
    }
        else{
      //When the value is close to or equal to ten digits
        if (i == 2)
        {
        inputNumber0 = (int) buf[0] - 0x30;
        Serial.print(buf);
        }
        else {
        inputNumber1 = (int) buf[0] - 0x30; 
        inputNumber0 = (int) buf[1] - 0x30;
        Serial.print(buf);
        }
        if (inputNumber1 > 0) 
//When the tens digit is greater than zero
           {
              for (int j = 0; j <= inputNumber1 - 1; j++) {
                Serial.print("**********\n");
              }
           }
           if (inputNumber0 > 0) 
//When the single digit is greater than zero 
           {
              for (int j = 0; j <= inputNumber0 - 1; j++) {
                Serial.print("*");
              }
              Serial.print("\n");
           }
    }
    stringComplete = false;
    i = 0;
    inputNumber0 = 0;
    inputNumber1 = 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);
}