dataQ = {}
dataQ.first = 0
dataQ.last = -1
dataQ.data = {}

function insert(q, val)
  q.last = q.last + 1
  q.data[q.last] = val
end

function remove(q)
    if (q.first > q.last) then 
      rval = -1
    else
      print("remove: q.data[q.first]= ", q.data[q.first], "  q.first= ", q.first)
      local rval = q.data[q.first]
      print("remove: rval= ", rval)
      q.data[q.first] = nil        -- to allow garbage collection
      q.first = q.first + 1
      print("remove: q.first= ", q.first)
    end
    return rval
end

insert(dataQ,"a")
insert(dataQ,"b")
insert(dataQ,"c")
for i,v in ipairs(dataQ.data) do
    print(i, v)
end
repeat
    local x = remove(dataQ)
    print("list item= ", x)
until (dataQ.first > dataQ.last)

-- your code goes here