/*

 Program Calculator Arduino

 */

#include <LiquidCrystal_I2C.h>

#include <Keypad.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const byte ROWS = 4; // Four rows

const byte COLS = 4; // Three columns

// Define the Keymap

char hexaKeys[ROWS][COLS] = {


  {'1', '2', '3', 'A'},

  {'4', '5', '6', 'B'},

  {'7', '8', '9', 'C'},

  {'*', '0', '#', 'D'}

};

byte rowPins[ROWS] = {10, 9, 8, 7};

byte colPins[COLS] = {6, 5, 4, 3};

Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS ); //  Create the Keypad

 long Num1,Num2,angka;

 char key,action;

 boolean hasil = false;

void setup() {

  // put your setup code here, to run once:

  Serial.begin(9600);

lcd.init();                      // initialize the lcd

lcd.init();

// Print a message to the LCD.

lcd.backlight();

lcd.print("Calculator Ard"); //Display a intro message

lcd.setCursor(0, 1);   // set the cursor to column 0, line 1

lcd.print("By: Indobot "); //Display a intro message

delay(2000); //Wait for display to show info

lcd.clear(); //Then clean it

}

void loop() {

  // put your main code here, to run repeatedly:

key = customKeypad.getKey(); //storing pressed key value in a char

if (key!=NO_KEY)

DetectButtons();

if (hasil==true)

Calculatehasil();

Displayhasil();  

}

void DetectButtons()

{

     lcd.clear();

    if (key=='*')

    {Serial.println ("Button Cancel"); angka=Num1=Num2=0; hasil=false;}

     if (key == '1')

    {Serial.println ("Button 1");

    if (angka==0)

    angka=1;

    else

    angka = (angka*10) + 1;

    }

     if (key == '4')

    {Serial.println ("Button 4");

    if (angka==0)

    angka=4;

    else

    angka = (angka*10) + 4;

    }

     if (key == '7')

    {Serial.println ("Button 7");

    if (angka==0)

    angka=7;

    else

    angka = (angka*10) + 7;

    }

    if (key == '0')

    {Serial.println ("Button 0");

    if (angka==0)

    angka=0;

    else

    angka = (angka*10) + 0;

    }

     if (key == '2')

    {Serial.println ("Button 2");

     if (angka==0)

    angka=2;

    else

    angka = (angka*10) + 2;

    }

     if (key == '5')

    {Serial.println ("Button 5");

     if (angka==0)

    angka=5;

    else

    angka = (angka*10) + 5;

    }

     if (key == '8')

    {Serial.println ("Button 8");

     if (angka==0)

    angka=8;

    else

    angka = (angka*10) + 8;

    }  

    if (key == '#')

    {Serial.println ("Button Equal");

    Num2=angka;

    hasil = true;

    }

   

     if (key == '3')

    {Serial.println ("Button 3");

     if (angka==0)

    angka=3;

    else

    angka = (angka*10) + 3;

    }

     if (key == '6')

    {Serial.println ("Button 6");

    if (angka==0)

    angka=6;

    else

    angka = (angka*10) + 6;

    }

     if (key == '9')

    {Serial.println ("Button 9");

    if (angka==0)

    angka=9;

    else

    angka = (angka*10) + 9;

    } 


      if (key == 'A' || key == 'B' || key == 'C' || key == 'D') //Detecting Buttons on Column 4

  {

    Num1 = angka;   

    angka =0;

    if (key == 'A')

    {Serial.println ("Addition"); action = '+';}

     if (key == 'B')

    {Serial.println ("Subtraction"); action = '-'; }

     if (key == 'C')

    {Serial.println ("Multiplication"); action = '*';}

     if (key == 'D')

    {Serial.println ("Devesion"); action = '/';} 

    delay(100);

  }

}

void Calculatehasil()

{

  if (action=='+')

    angka = Num1+Num2;




  if (action=='-')

    angka = Num1-Num2;

  if (action=='*')

    angka = Num1*Num2;

  if (action=='/')

    angka = Num1/Num2;

}

void Displayhasil()

{

  lcd.setCursor(0, 0);  

  lcd.print(Num1); lcd.print(action); lcd.print(Num2);

  if (hasil==true)

  {lcd.print(" ="); lcd.print(angka);}

  lcd.setCursor(0, 1);  

  lcd.print(angka);

}