/* 
Serial read from serial monitor
(while using one method, comment the other one.
  setup for both methods is same, however loop is different)

1st method :
  Serial.read() function is used to read the message by reading one char at a time. 
  To convert string (char array) to int, the atoi() function is used.

2nd method :
  Serial.readString() is used to directly read the entire message (string)
  To convert String (object) to int, the toInt() function is used
*/

void setup(){
  Serial.begin(9600);
  Serial.println("hello world");
}


/*      method 1 :      */
void loop(){
  // function to read data from serial monitor
  while(Serial.available() > 0){
    static char message[12];
    static int msg_pos = 0;

    char inByte = Serial.read();
    if(inByte != '\n'){
      message[msg_pos] = inByte;
      msg_pos++;
    }
    else{
      message[msg_pos] = '\0';
      int num_msg = atoi(message);
      if(num_msg != 0){
        Serial.print("Num : ");
        Serial.println(num_msg);
      } 
      else{
        Serial.print("Str : ");
        Serial.println(message);
      }
      msg_pos = 0;
    }
  } 
}


/*      method 2:     */
void loop(){
  if(Serial.available() > 0){
    String message = Serial.readString();
    int num_msg = message.toInt();
    if(num_msg != 0){
      Serial.print("Num :");
      Serial.println(num_msg);
    }
    else{
      Serial.print("Str : ");
      Serial.println(message);
    }
  }
}