Let's have a look at a basic use case for tuples that we most probably already know. We can define a structure as follows, in order to just bundle some variables:

struct Foo {
    int a;
    string b;
    float c;
};

Instead of defining a structure as in the preceding example, we can also define a tuple:

using Foo = tuple<int, string, float>;

We can access its items using the index number of the type from the type list. In order to access the first member of a tuple, t, we can use std::get<0>(t) to access the second member we write std::get<1>, and so on. If the index number is too large, then the compiler will even safely error out.

Throughout the book, we have already used the decomposition capabilities of C++17 for tuples. They allow us to decompose a tuple quickly by just writing auto [a, b, c] = some_tuple in order to access its individual items.

Composing and decomposing single data structures are not the only things we can do with tuples. We can also concatenate or split tuples, or do all kinds of magic. In this recipe, we will play around with such capabilities in order to learn how to do it.