Reddit Uno alphanumeric counter v1.0

/*
  September 17, 2019
  Reddit Uno alpha-numeric counter with 'R' reset  v1.0

  tested on a China clone Uno--it works?
*/

#include<stdio.h> // ------------------- I don't know that you need to include this just to use Serial? It doesn't hurt, I suppose...

unsigned long SerialTimer;
char alpha = 'A';
char number = '0';

void setup() {
  SerialTimer = millis();
  Serial.begin(9600);
}


void loop() {
  while (alpha <= 'Z') {
    if (millis() - SerialTimer >= 500) {
      Serial.print(alpha);
      Serial.println(number); // --------------- I changed Serial.print(number) to Serial.println(number), so that it would print on successive lines.
      alpha++;
      number++;
      if (alpha > 'Z') //{
        alpha = 'A';
      //}
      if (number > '9') //{
        number = '0';
      //}
      SerialTimer += 500;
    }
    if (Serial.available() != 0) { // ------------- This works but it can cause issues sometimes, with line-ending characters.
      //while (Serial.available()) { // --------------- It is generally better to use a while() loop to read the serial buffer, so that it gets emptied on every reading.
      //                                                But in this case, the code works either way.
      if (Serial.read() == 'R') {
        alpha = 'A';
        number = '0';
      }
    }
  }
}





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