test1

local sensor = peripheral.wrap("top")
local bsensor = peripheral.wrap("openperipheral_sensor_1")
local monitor = peripheral.wrap("monitor_3")

monitor.clear()
monitor.setCursorPos(1,1)

local pIn = {}

function welcome()
  monitor.write("Welcome!")
  monitor.setCursorPos(1,2)
  monitor.write(username)
  sleep(2)
  monitor.clear()
end

function getUserOut()
  playersb = bsensor.getPlayers()
  if playersb[1] == nil then
       -- No one is outside
  else
    usernameOut = playersb[1].name
    monitor.setCursorPos(1,1)

    for x, y in pairs(pIn) do
      if x == usernameOut then
        monitor.write("Goodbye")
        monitor.setCursorPos(1,2)
        monitor.write(usernameOut)
        sleep(1)
        monitor.clear()
        remove = "true"
      end
    end
    if remove == "true" then
      pIn[usernameOut] = nil
      remove = "false"
    end
  end
end

function getUser()
  players = sensor.getPlayers()
  if players[1] == nil then
    username = "null"
  else
    username = players[1].name
    if next(pIn) == nil then
      -- table null
      welcome()
      pIn[username] = "1"
    else
      for n, a in pairs(pIn) do
        if n == username then
        local n = username
          -- Player has already been in the shop
          remove0 = "true"
        else
          welcome()
          pIn[username] = "1"
        end
      end
      if remove0 == "true" then
        getUserOut()
        remove0 = "false"
      end
    end
  end
end

while true do
  monitor.setCursorPos(1,1)
  getUser()
  getUserOut()
  sleep(0.75)
end