Testing the LCD screen

We are now ready to test the LCD screen. The following is the complete code that I've used to do so:

// Libraries
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <SD.h>
#include <Ethernet.h>

// LCD Screen
LiquidCrystal_I2C lcd(0x27,20,4);

void setup()
{
  // Initialize LCD screen
  initDisplay();
  
}

void loop()
{
  // Print message on the LCD screen
  lcd.setCursor(0,0);
  lcd.println("This is a test of the LCD screen!");
}

// Initialize LCD screen
void initDisplay()
{
  lcd.init();      
  lcd.backlight();
  lcd.clear();
}

Let's look at the code line by line:

The first part of the code includes the libraries that we need in order to carry out this project. The four libraries that you should include are Wire.h, LiquidCrystal_I2C.h, SD.h, and Ethernet.h:

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

Then, we declare the LCD instance. If you have used a different screen...