#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);

void setup()
{
  lcd.begin(16, 2);
  lcd.clear();

  Serial.begin(9600);

  pinMode(8, INPUT);
  digitalWrite(8, HIGH);
  pinMode(9, INPUT);
  digitalWrite(9, HIGH);
}
double i = 0;
double a = millis();
double c ;

void loop()
{
  lcd.clear();
  lcd.print("press start");
  delay(100);

  if (digitalRead(8) == LOW)
  {

    lcd.clear();
    a = millis();
    while (digitalRead(9) == HIGH)
    {

      c = millis();
      i = (c - a) / 1000;
      lcd.print(i);
      lcd.setCursor(7, 0);
      lcd.print("Sec's");
      lcd.setCursor(0, 0);
      Serial.println(c);
      Serial.println(a);
      Serial.println(i);
      Serial.println("......");
      delay(100);
    }

    if (digitalRead(9) == LOW)
    {
      while (digitalRead(8) == HIGH)
      {
        lcd.setCursor(0, 0);
        lcd.print(i);
        lcd.setCursor(11, 0);
        lcd.print("");
        lcd.setCursor(0, 0);
        delay(100);
      }
    }
  }
}