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

LiquidCrystal_I2C lcd(32, 16, 2); // set the LCD address to 0x3F for a 16 chars and 2 line display
int PB = 2;

void scrollMessage(int row, String message, int delayTime, int totalColumns)
{
  for (int i = 0; i < totalColumns; i++)
  {
    message = " " + message;
  }

  message = message + " ";
  for (int position = 0; position < message.length(); position++)
  {
    lcd.setCursor(0, row);
    lcd.print(message.substring(position, position + totalColumns));
    delay(delayTime);
  }
}

void setup()
{
  pinMode(PB, INPUT_PULLUP);
  lcd.init();
  lcd.clear();
  lcd.backlight();
}

void loop()
{
  while (digitalRead(PB) == 1)
  {
    lcd.setCursor(1, 0);
    lcd.print("Hello World");
    delay(500);

    scrollMessage(1, "Welcome!", 250, 16);
  }

  if (digitalRead(PB) == 0)
  {
    lcd.clear();
    lcd.setCursor(1, 0);
    lcd.print("Let's begin!");
  }
}