#include <LiquidCrystal_I2C.h>

//initialize lcd
LiquidCrystal_I2C lcd(0x27,16,2);

//setting hours, minutes, secound  and miliseconds to 0
int h=0;     
int m=0;     
int s=0;     
int ms=0;    

//defines pin for all buttons
int startstopPin = 3;    
int startstopLED = 4;    
int resetPin = 2;   
    
//defines starting  points
int start=0;
int stop=0;
int reset=0;
int startstopState=0;

void setup() 
{  
  
  lcd.init();
  lcd.clear();         
  lcd.backlight();      // Make sure backlight is on
   
  //defining pins  if they are INPUT or OUTPUT pins
  pinMode(startstopPin, INPUT_PULLUP);  
  pinMode(startstopLED, OUTPUT);
  pinMode(resetPin, INPUT_PULLUP);
  
} 
void loop() 
{ 
  
  lcd.setCursor(3,1); 
  lcd.print("STOPWATCH");  
  lcd.setCursor(3,0);  
  lcd.print("TIME:"); 
  lcd.print(h); 
  lcd.print(":"); 
  lcd.print(m);  
  lcd.print(":"); 
  lcd.print(s);
  
 start = digitalRead(startstopPin);  //reading buton state
 if(start == LOW) 
 {
  stopwatch();  //calls the  stopwatch function
  digitalWrite(startstopPin, HIGH);  
 }
}

void stopwatch()
{     
  lcd.setCursor(3,0);   //setting start point on lcd 
  lcd.print("TIME:");   //display TIME
  lcd.print(h);         //display hours
  lcd.print(":");      
  lcd.print(m);         //display minutes
  lcd.print(":"); 
  lcd.print(s);         //display seconds
  lcd.setCursor(3,1);
  lcd.print("         ");
 
  ms=ms+100;           
  delay(10); 
   
 if(ms==590)           
  {
   
   ms=0; 
   s=s+1; 
  }
  
  if(s==60)     //if state for counting up minutes
  { 
  s=0; 
  m=m+1; 
  }

  if(m==60)      //if state for counting up hours
  {  
  m=00; 
  h=h+01;  
  } 
   
   

   stop = digitalRead(startstopPin);  //reading buton  state
if(stop == LOW)    //checking if button is pressed
{
  stopwatch_stop();   //calls the stopwatch_stop function
  digitalWrite(startstopPin, LOW);  
}
  else
  {
   stopwatch();    //calls the stopwatch function
  }
}

void stopwatch_stop()
{
  lcd.setCursor(3,0); 
  lcd.print("TIME:"); 
  lcd.print(h); 
  lcd.print(":");  
  lcd.print(m); 
  lcd.print(":"); 
  lcd.print(s);
  lcd.setCursor(3,1);
  lcd.print("         ");
      
    
   start = digitalRead(startstopPin);   //reading buton state
 if(start == LOW)
 {
  stopwatch();    //calls  the stopwatch function
  digitalWrite(startstopPin, HIGH);  
 } 
 
 reset = digitalRead(resetPin);   //reading  buton state
 if(reset == LOW)
 {
   stopwatch_reset();    //calls the  stopwatch_reset function
   loop();
  }
 else
 {
  stopwatch_stop();    //calls the stopwatch_stop function
 }
}

void stopwatch_reset()
{
  lcd.clear();
 h=00;    //seting hours to 0
 m=00;    //seting minutes to 0
  s=00;    //seting seconds to 0
 return;  //exiting the program and returning  to the point where entered the program
}