Implementing Ranges for Custom Types

How to use concepts with custom ranges in C++?

How can I use concepts to ensure my custom type is a valid range in C++?

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Using concepts with custom ranges in C++ allows you to enforce constraints at compile time, ensuring your custom type meets the criteria of a range.

Concepts from the <ranges> header can be used to assert properties like random_access_range and contiguous_range. Here’s how:

#include <vector>
#include <ranges>
#include <string>

class Player {
public:
  Player(std::string Name) : mName(Name) {}
  std::string GetName() const { return mName; }
private:
  std::string mName;
};

class Party {
public:
  void AddMember(const std::string& NewMember) {
    PartyMembers.emplace_back(NewMember);
  }

  auto begin() {
    return PartyMembers.begin();
  }
  auto end() {
    return PartyMembers.end();
  }

private:
  std::vector<Player> PartyMembers;
};

static_assert(std::ranges::random_access_range<Party>);
static_assert(std::ranges::contiguous_range<Party>);

int main() {
  Party MyParty;
  MyParty.AddMember("Legolas");
  MyParty.AddMember("Gimli");
  MyParty.AddMember("Frodo");

  for (const auto& Player : MyParty) {
    std::cout << Player.GetName() << '\n';
  }
}
Legolas
Gimli
Frodo

Using static_assert with concepts ensures that your custom type Party remains a valid range, and any violations will be caught at compile time.

This Question is from the Lesson:

Implementing Ranges for Custom Types

Learn to implement iterators in custom types, and make them compatible with range-based techniques.

Answers to questions are automatically generated and may not have been reviewed.

This Question is from the Lesson:

Implementing Ranges for Custom Types

Learn to implement iterators in custom types, and make them compatible with range-based techniques.

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