Arduino Totalizer

/*
 * Arduino Totalizer
 *
 * learnelectronics
 * 12 DEC 2017
 *
 * www.youtube.com/c/learnelectronics
 * [email protected]
 *
 * note: range: +/- 5-300Hz
 */

#include <Wire.h>                                     //I2C Driver for OLED
#include <Adafruit_SSD1306.h>                         //OLED Driver

#define OLED_RESET 4                                  //for oled

Adafruit_SSD1306 display(OLED_RESET);                 //create instance of SS1306 called display

long count = 0;                                       //declare var for counting
int flag = 0;                                         //declare variable for stop flag

void setup()   {

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);          //start OLED @ hex addy 0x3c
  display.display();                                  //initialize display
  display.clearDisplay();
  pinMode(8,INPUT);                                   //set dig pin 8 as input
  pinMode(12,INPUT_PULLUP);                           //set dig pin 12 as input w/internal pullup

}

void loop() {

int stopnow = digitalRead(12);                        //check if stop switch is pressed
if(stopnow == 0)flag = 1;                             //if stop switch has been pressed set flag
int check = digitalRead(8);                           //check for a pulse
if(check==1 && flag == 0)count++;                     // if the pulse is high AND the flag is not set increment count

  display.clearDisplay();
  display.setTextSize(3);
  display.setTextColor(WHITE);
  display.setCursor(0,0);
  display.println(count);                             //show the count
  display.display();
}