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C++ Academy · Lesson

Common Standard Concepts Integral Ranges

Use standard library concepts like integral and ranges::range.

Common Standard Concepts Integral Ranges is a free C++ Academy lesson on CoddyKit — lesson 4 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the C++ Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

The Standard Concept Library

C++20 introduced many standard concepts in <concepts> and <ranges>. Knowing them saves writing your own.

Core Language Concepts

The fundamental concepts:

  • std::same_as<T, U>
  • std::derived_from<T, U>
  • std::convertible_to<T, U>
  • std::common_with<T, U>
  • std::assignable_from<T, U>

Arithmetic Concepts

Restrict to numeric types:

  • std::integral — any integer type
  • std::signed_integral — signed integer
  • std::unsigned_integral — unsigned integer
  • std::floating_point — float, double, long double
template <std::floating_point T>
T mean(T a, T b) { return (a + b) / 2; }

Comparison Concepts

Constrain types for equality and ordering:

  • std::equality_comparable
  • std::totally_ordered
  • std::three_way_comparable

Object Concepts

Common requirements:

  • std::movable
  • std::copyable
  • std::default_initializable
  • std::semiregular
  • std::regular
template <std::regular T>
class Container { /* full-fledged value type */ };

Callable Concepts

For functions and functors:

  • std::invocable<F, Args...>
  • std::regular_invocable<F, Args...>
  • std::predicate<F, Args...>
template <std::invocable<int> F>
void apply_to_42(F&& f) {
    std::forward<F>(f)(42);
}

Iterator Concepts

In <iterator>:

  • std::input_iterator
  • std::forward_iterator
  • std::bidirectional_iterator
  • std::random_access_iterator
  • std::contiguous_iterator

Ranges Concepts (C++20)

From <ranges>:

  • std::ranges::range — has begin/end
  • std::ranges::view — non-owning range
  • std::ranges::sized_range — knows its size in O(1)
  • std::ranges::random_access_range
template <std::ranges::range R>
auto first(R&& r) {
    return *std::ranges::begin(r);
}

Combining Concepts

Mix concepts to express precise requirements.

template <std::ranges::random_access_range R>
    requires std::integral<std::ranges::range_value_t<R>>
auto sum(const R& r) {
    return std::reduce(std::ranges::begin(r), std::ranges::end(r));
}

Custom Concepts on Top

Build domain-specific concepts on top of standard ones.

template <typename T>
concept Number = std::integral<T> || std::floating_point<T>;

Concept-Backed Algorithms

C++20 ranges algorithms are heavily concept-constrained. Their error messages directly say which concept failed when you pass an unsuitable type.

Cheat Sheet

Use built-in concepts whenever possible:

  • Numbers → integral / floating_point
  • Iteration → ranges::range
  • Callable → invocable / predicate
  • Value type → regular or semiregular

Quick Check

Which standard concept describes a type that has both begin() and end()?

Recap

The standard library ships rich concept libraries: arithmetic (integral, floating_point), comparable (equality_comparable), object (movable, regular), invocable, iterator, and range. Use them as the foundation for your own constraints.

Frequently asked questions

Is the “Common Standard Concepts Integral Ranges” lesson free?

Yes — the full text of “Common Standard Concepts Integral Ranges” is free to read here on the web, and the C++ Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the C++ Academy course, upgrade to CoddyKit PRO.

What will I learn in “Common Standard Concepts Integral Ranges”?

Use standard library concepts like integral and ranges::range. You practise C++ Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start C++ Academy?

No prior experience is required. C++ Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 4 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Common Standard Concepts Integral Ranges” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this C++ Academy lesson?

Yes. Every C++ Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. Why Concepts vs SFINAE
  2. Defining Concepts with requires
  3. Using Concepts in Templates and auto
  4. Common Standard Concepts Integral Ranges
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