Class MyItem

extern/imgui/imgui_demo.cpp:3690–3734

};

struct MyItem
{
    int         ID;
    const char* Name;
    int         Quantity;

    // We have a problem which is affecting _only this demo_ and should not affect your code:
    // As we don't rely on std:: or other third-party library to compile dear imgui, we only have reliable access to qsort(),
    // however qsort doesn't allow passing user data to comparing function.
    // As a workaround, we are storing the sort specs in a static/global for the comparing function to access.
    // In your own use case you would probably pass the sort specs to your sorting/comparing functions directly and not use a global.
    // We could technically call ImGui::TableGetSortSpecs() in CompareWithSortSpecs(), but considering that this function is called
    // very often by the sorting algorithm it would be a little wasteful.
    static const ImGuiTableSortSpecs* s_current_sort_specs;

    // Compare function to be used by qsort()
    static int IMGUI_CDECL CompareWithSortSpecs(const void* lhs, const void* rhs)
    {
        const MyItem* a = (const MyItem*)lhs;
        const MyItem* b = (const MyItem*)rhs;
        for (int n = 0; n < s_current_sort_specs->SpecsCount; n++)
        {
            // Here we identify columns using the ColumnUserID value that we ourselves passed to TableSetupColumn()
            // We could also choose to identify columns based on their index (sort_spec->ColumnIndex), which is simpler!
            const ImGuiTableColumnSortSpecs* sort_spec = &s_current_sort_specs->Specs[n];
            int delta = 0;
            switch (sort_spec->ColumnUserID)
            {
            case MyItemColumnID_ID:             delta = (a->ID - b->ID);                break;
            case MyItemColumnID_Name:           delta = (strcmp(a->Name, b->Name));     break;
            case MyItemColumnID_Quantity:       delta = (a->Quantity - b->Quantity);    break;
            case MyItemColumnID_Description:    delta = (strcmp(a->Name, b->Name));     break;
            default: IM_ASSERT(0); break;
            }
            if (delta > 0)
                return (sort_spec->SortDirection == ImGuiSortDirection_Ascending) ? +1 : -1;
            if (delta < 0)
                return (sort_spec->SortDirection == ImGuiSortDirection_Ascending) ? -1 : +1;
        }

        // qsort() is instable so always return a way to differenciate items.
        // Your own compare function may want to avoid fallback on implicit sort specs e.g. a Name compare if it wasn't already part of the sort specs.
        return (a->ID - b->ID);
    }
};
const ImGuiTableSortSpecs* MyItem::s_current_sort_specs = NULL;
}