Homework 3 Notes

1. Instructions

This assignment is about code modernization. We are tasked with refactoring the codebase to use modern C++ features, then writing unit tests to ensure that the code still works as expected.

2. Examples of Code Modernization

2.1 Almost always auto for variable declarations:

// Before
int caveId = pCave->GetCaveId();
// After
auto caveId = pCave->GetCaveId();

2.2 Use range-based for loops:

// Before
for (auto it = m_denizens.begin(); it != m_denizens.end(); ++it)
{
    if ((*it)->ObserveCaveEntrance(newDenizen))
    {
        // Stop if that denizen affected things.
        break;
    }
}

// After
for (auto&& denizen : m_denizens)
{
    if (denizen->ObserveCaveEntrance(newDenizen))
    {
        // Stop if that denizen affected things.
        break;
    }
}

2.3 Use STL algorithms:

// Before
void Cave::RemoveDenizen(const DenizenIdentifier& identifier)
{
    std::set<std::shared_ptr<Denizen>>::const_iterator itr;

    for (itr = m_denizens.begin(); itr != m_denizens.end(); ++itr)
    {
        std::shared_ptr<Denizen> denizen = *itr;

        const DenizenIdentifier& id = denizen->GetIdentifier();

        if (id.m_category == identifier.m_category &&
            id.m_instance == identifier.m_instance)
        {
            break;
        }
    }

    if (itr != m_denizens.end())
    {
        m_denizens.erase(itr);
    }
}


// After
void Cave::RemoveDenizen(const DenizenIdentifier& identifier)
{
    m_denizens.erase(std::ranges::find_if(m_denizens,
                        [&](const auto& thing)
                        { 
                            return thing->GetIdentifier() <=> identifier == std::strong_ordering::equal; 
                        }));
}

// Before 
bool Cave::HasDenizen(const DenizenIdentifier& identifier) const
{
    std::set<std::shared_ptr<Denizen>>::const_iterator itr;

    for(itr = m_denizens.begin(); itr != m_denizens.end(); ++itr)
    {
        std::shared_ptr<Denizen> denizen = *itr;
        const DenizenIdentifier &id = denizen->GetIdentifier();

        if(id.m_category == identifier.m_category)
        {
            break;
        }
    }

    return itr != m_denizens.end();
}

// After
bool Cave::HasDenizen(const DenizenIdentifier& identifier) const
{
    return std::ranges::find_if(m_denizens, [&](const auto& denizen)
        {
            return denizen->GetIdentifier().m_category == identifier.m_category;
        }) != m_denizens.end();
}