We process lines on Arduino

1. We go to arduino.ru and look in the type column for everything related to the characters.
   
   • Char data type
   • Text strings as an array of characters
   • String object created in version 0.0.19
   
   
2. We decide what form of representation we will use (I stopped at the String class, because I had an unpleasant experience with a mash-up array).
3. Convulsively trying to write our function with preference and professional mesh
4. We are looking for a detailed description of the class.
5. We are looking for the necessary operators.
6. We write!

1. Cyclically check whether there is a readable byte in the com port buffer, if there is, read.
2. If the received byte is a newline character ('\ n'), then we call the self-writing function of parsing, if not, then add the received byte to the created variable of the String type.
3. Parsim, finally, a string.

   In fact, because the practical use of string parsing is not on my mind, this function is merely demonstrative in nature, comparing the resulting string with the constant string already recorded in memory. So, using the equals operator, we compare the accepted string with the written one, and, if the operator returns true, we exit the handler function, if not, we compare it with the next one. If the strings are equivalent, then again, exit the handler function, returning the result. Well, if even this condition does not work, then we still exit the function and say that the string is not true.
   
4. Depending on the received result with the switch case, select the desired one.
5. Reset the accepted string, then begin to collect it again.

#define led 13 String input_string = ""; const String Led_off = "switch led off"; const String Led_on = "switch led on"; bool led_running; void setup() { Serial.begin(9600); } void loop() { while (Serial.available() > 0) { char c = Serial.read(); if (c == '\n') { Serial.print("Input_string is: "); Serial.println(input_string); switch ( parse(input_string, Led_off, Led_on) ) { case 10: led_running=false; Serial.println("Switching off is done"); break; case 11: led_running=true; Serial.println("Switching on is done"); break; case 0: Serial.println("invalid String"); break; } input_string = ""; digitalWrite(led, led_running); } else { input_string += c; } } } byte parse(String input_string, const String Led_off, const String Led_on) { if (input_string.equals(Led_off) == true) { return 10; } else if (input_string.equals(Led_on) == true) { return 11; } else return 0; } 

 pinMode(led, OUTPUT);