Question

My aim is to set up a data structure to store the settings of my application.

In PHP I would just write…

$settings = array(
    "Fullscreen" => true,
    "Width"      => 1680,
    "Height"     => 1050,
    "Title"      => "My Application",
);

Now I tried to create a similar structure in C++ but it can’t handle different datatypes yet. By the way if there is a better way of storing such settings data, please let me know.

struct Setting{ string Key, Value; };

Setting Settings[] = {
    ("Fullscreen", "true"),     // it's acceptable to store the boolean as string
    ("Width", "1680"),          // it's not for integers as I want to use them later
    ("Height", 1050),           // would be nice but of course an error
    ("Title", "My Application") // strings aren't the problem with this implementation
};

How can I model a structure of an associative array with flexible datatypes?

Answer 1

An associative data structure with varying data types is exactly what a struct is…

struct SettingsType
{
    bool Fullscreen;
    int Width;
    int Height;
    std::string Title;
} Settings = { true, 1680, 1050, "My Application" };

Now, maybe you want some sort of reflection because the field names will appear in a configuration file? Something like:

SettingsSerializer x[] = { { "Fullscreen", &SettingsType::Fullscreen },
                           { "Width",      &SettingsType::Width },
                           { "Height",     &SettingsType::Height },
                           { "Title",      &Settings::Title } };

will get you there, as long as you give SettingsSerializer an overloaded constructor with different behavior depending on the pointer-to-member type.