#include <Keypad.h>
#include <LiquidCrystal.h>
 int num1add;
  int sumadd;
   int num2add;
    int num1sub;
      int sumsub;
        int num2sub;
          int num1mul;
            int num2mul;
              int summul;
                float num1div;
                    int num2div;
                        float sumdiv;
                    int rs=10;
                int en=11;
            int d4=12;
          int d5=13;
      int d6=A0;
  int d7=A1;
LiquidCrystal lcd(rs,en,d4,d5,d6,d7);


String prevOp="q";
// Define the keypad
const byte ROWS = 4; // Four rows
const byte COLS = 4; // Four columns
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {9, 8, 7, 6}; // Connect to the row pinouts of the keypad
byte colPins[COLS] = {5, 4, 3, 2}; // Connect to the column pinouts of the keypad

// Create the Keypad
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

String inputString = ""; // String to hold the number

void setup() {
  Serial.begin(9600); // Start the serial communication
  Serial.println('hi');
  lcd.begin(16,2);
  
}

void loop() {
  char key = keypad.getKey(); // Get the key pressed
 inputString.trim();
 int inputNumbar =inputString.toInt();
  if (key) {
    if (key == '#'&&prevOp=="q") { // If '#' is pressed, print the number and reset the string
      Serial.println(inputNumbar);
      inputString = ""; 
    lcd.clear();
    lcd.print(inputNumbar);
      // Clear the input string
    }
               if(key=='#'&& prevOp=="+"){
                num2add=inputNumbar;
                   sumadd=num1add+num2add;
                     Serial.println(sumadd);
                       prevOp="q";
                         inputString="";
                           lcd.clear();
                              lcd.print(sumadd);
                                        }
                  if(key=='#' && prevOp=="-"){
              num2sub=inputNumbar;
           sumsub=num1sub-num2sub;
        Serial.println(sumsub);
     prevOp="q";
 inputString="";
  lcd.clear();
  lcd.print(sumsub);
}
                if(key=='#' && prevOp=="*"){
                    num2mul=inputNumbar;
                       summul=num1mul*num2mul;
                        Serial.println(summul);
                           inputString="";
                              lcd.clear();
                                 lcd.print(summul);
                                    }
                if(key=='#' && prevOp=="/"){
                num2div=inputNumbar;
          sumdiv=num1div/num2div;
    Serial.println(sumdiv);
inputString="";
  lcd.clear();
  lcd.print(sumdiv);
}
     else if (key >= '0' && key <= '9') { // If a number is pressed, add it to the string
      inputString += key;
     
     lcd.print(key);
    
    
    }
    else if(key=='A'){
      num1add=inputNumbar;
     inputString="";
     prevOp="+";
     lcd.clear();
     
     
    }
    else if(key=='B'){
      num1sub=inputNumbar;
      inputString="";
      prevOp="-";
      lcd.clear();
      
     
    }
    else if(key=='C'){
      num1mul=inputNumbar;
      inputString="";
      prevOp="*";
      lcd.clear();
      
      
    }
    else if(key=='D'){
      num1div=inputNumbar;
      inputString="";
      prevOp="/";
      lcd.clear();
      
      
    }
else if(key=='*'){
  inputString="";
  prevOp="q";
  num1add=0;
 sumadd=0;
 num2add=0;
 num1sub=0;
 sumsub=0;
num2sub=0;
 num1mul=0;
 num2mul=0;
 summul=0;
 num1div=0;
 num2div=0;
 sumdiv=0;
 lcd.clear();
}
  }

 
}