My_inventory.lua

function isWeight(max, current, item)
    current = current + item
    if current > max then 
        print("The object is too heavy.")
        return false
    else
        return true
    end
end

function createInventory(maxWeight)
    local Inventory = {}
    local MaxWeight = maxWeight
    local weight = 0
    local items = {}

    Inventory.addItem =function(item)
        if  type(item) =="table" and item.name ~= nil and item.weight ~= nil and type(item.name) =="string"  and type(item.weight) == "number" and item.weight > 0 then
            if isWeight(MaxWeight, weight, item.weight) == true then
                weight = weight + item.weight
                table.insert(items, item)
                return weight
            end
        else
            print("ERROR : incorect value !!")
            return -1
        end
    end

    Inventory.removeItem = function(itemName)
        if #items == 0 then
            print("The inventory is empty")
            return 0
        elseif type(itemName) == "string" and itemName ~= nil then   
            for index = #items, 1, -1 do
                if items[index].name == itemName then
                    local removedWeight = items[index].weight
                    table.remove(items, index)
                    weight = weight - removedWeight
                end
            end
        else
            print("ERROR : incorect value !!")
            return -1
        end
        return weight
    end

    Inventory.getTotalWeight = function()
        return weight
    end

    Inventory.listItems = function()
        if #items == 0 then
            print("The inventory is empty")
        else
            for index, item in ipairs(items) do
                print ("Name object : "..item.name.." The weight of the object : " ..item.weight)
            end
        end
    end
    return Inventory
end

    local inventory = createInventory(100)
    inventory.addItem({name="epee", weight=5})
    inventory.addItem({name="eau", weight=10})
    inventory.addItem({name="nouriture", weight=30})
    inventory.addItem({name="jsp", weight=9})


    inventory.listItems()
    print("Total : "..inventory.getTotalWeight())
    print(inventory.removeItem("epee"))