#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Initialize LCD I2C: address 0x27, 16 columns, 2 rows
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  Serial.begin(9600); // Start serial communication
  lcd.init();         // Initialize the LCD
  lcd.backlight();    // Turn on the LCD backlight

  lcd.setCursor(0, 0);
  lcd.print("Enter expr:");
  Serial.println("Enter two numbers to add (e.g., 1 + 1):");
}

void loop() {
  if (Serial.available()) { // Check if input is available
    lcd.clear();            // Clear the LCD
    lcd.setCursor(0, 0);

    // Read input from Serial Monitor
    String input = Serial.readStringUntil('\n'); // Read input until newline
    input.trim(); // Remove extra spaces

    // Variables for the numbers
    float num1 = 0, num2 = 0;

    // Parse the input for addition only
    if (sscanf(input.c_str(), "%f + %f", &num1, &num2) == 2) {
      float result = num1 + num2; // Perform addition

      // Display the result on the LCD
      lcd.print("Result:");
      lcd.setCursor(0, 1);
      lcd.print(result);
      Serial.println("Result: " + String(result));
    } else {
      // Invalid input message
      lcd.print("Error: Invalid");
      Serial.println("Error: Please enter in format 'num1 + num2'");
    }

    delay(3000); // Wait for 3 seconds
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Enter expr:");
  }
}