Location display

-- Code for computer which displays destinations

display_receive_channel = 4

-- Start peripherals
display = peripheral.wrap("left")
modem = peripheral.wrap("bottom")
modem.open(display_receive_channel)

function clear_print(text)
    y_size, x_size = display.getSize()
    x_pos = (x_size - string.len(text)) / 2 + 6
    y_pos = y_size / 2 - 5
    --print(x_size.." "..y_size.." "..x_pos.." "..y_pos)
    print(text)

    display.clear()
    display.setCursorPos(x_pos, y_pos)
    display.write(text)
end

last_pressed = 0

while true do
    local event, modemSide, senderChannel, replyChannel,
        message, senderDistance = os.pullEvent("modem_message")

    last_pressed = tonumber(message)

    if     last_pressed == 0 then clear_print("No Destination")
    elseif last_pressed == 1 then clear_print("Sacred Oak")
    elseif last_pressed == 2 then clear_print("Redwood")
    elseif last_pressed == 3 then clear_print("Destination 3")
    elseif last_pressed == 4 then clear_print("Destination 4")
    end
end