#include <LiquidCrystal.h>
#include <Keypad.h>

/* Display */
LiquidCrystal lcd(12, 11, 10, 9, 8, 7);
int buttons[] = {6, A4, A5};

/* Keypad setup */
const byte KEYPAD_ROWS = 4;
const byte KEYPAD_COLS = 4;
byte rowPins[KEYPAD_ROWS] = {5, 4, 3, 2};
byte colPins[KEYPAD_COLS] = {A3, A2, A1, A0};
char keys[KEYPAD_ROWS][KEYPAD_COLS] = {
  {'1', '2', '3', '+'},
  {'4', '5', '6', '-'},
  {'7', '8', '9', '*'},
  {'.', '0', '=', '/'}
};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, KEYPAD_ROWS, KEYPAD_COLS);

String numberInput = ""; // Store the entered number as a string

void setup() {
  Serial.begin(9600);
  lcd.begin(16, 2);
  lcd.clear();
  lcd.cursor();
  lcd.setCursor(0, 0);
  for (int i = 0; i <= 2; i++) {
    pinMode(buttons[i], INPUT);
  }
}

void processInput(char key) {
  if (key == '>') {
    // When '>' is entered, convert the inputted number to an integer and display the result
    int enteredNumber = numberInput.toInt();
    int result;

    if (digitalRead(buttons[0]) == HIGH) {
      result = enteredNumber * 2;
    } else if (digitalRead(buttons[1]) == HIGH) {
      result = enteredNumber * 3;
    } else if (digitalRead(buttons[2]) == HIGH) {
      result = enteredNumber * 4;
    }

    lcd.clear();
    lcd.print("Result: ");
    lcd.print(result);
    numberInput = ""; // Clear the input for the next iteration
    delay(2000);
    lcd.clear();
  } else {
    lcd.print(key);
    numberInput += key; // Concatenate the entered digits to the numberInput string
  }
}

void loop() {
  char key = keypad.getKey();
  if (key) {
    processInput(key);
  }
}