[C++20 - 4th Emperor] Chapter 01. Concept

GitHub : https://github.com/developeSHG/CPP20-4th_Emperor/commit/978ee4946379c5c446ef2d1fb9e7f8354ec1e671

Concept · developeSHG/CPP20-4th_Emperor@978ee49

 

 

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// static void TestObject<T>(T obj) where T : GameObject
C#에는 제네릭 문법(C++의 템플릿과 유사)을 통해 타입을 동적으로 생성하면서
where를 통해 타입에 대해 부가적인 조건을 걸어 (어떤 클래스에 파생된다든지)
원하는 타입을 생성할 수 있었다.

 

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csharp

닫기 줄바꿈

using System;

namespace CSharp
{
‌class GameObject
‌{
‌‌public int id;
‌}

‌class Knight : GameObject
‌{

‌}

‌class Orc : GameObject
‌{

‌}

‌class Program
‌{
‌‌static void TestObject<T>(T obj) where T : GameObject
‌‌{
‌‌‌int id = obj.id;
‌‌}

‌‌static void Main(string[] args)
‌‌{
‌‌‌TestObject<Knight>(new Knight());
‌‌‌//TestObject<int>(3);	
‌‌}
‌}
}

// C++에서는 원하는 특정 조건에 대해 한정짓는 문법이 없었지만
// C++20에 오면서 추가되었다.
// 단순하긴 하지만, C#처럼 단순하진 않다. (4가지 방식이나 있기때문)

cpp

닫기 줄바꿈

#include <iostream>
#include <iostream>
using namespace std;
#include <list>
#include <algorithm>
// 오늘의 주제 : Concept (컨셉)

// 1) Requires Clause(절)
template<typename T>
requires std::integral<T> // 정수만 받아주고, 소수점이 들어가는 수는 제외
void TestConcept1(T number)
{
‌cout << number << endl;
}

// 2) Trailing Requires Clause (뒤에 붙는~)
template<typename T>
void TestConcept2(T number) requires std::integral<T>
{
‌cout << number << endl;
}

// 3) Constrained Template Parameter (강요된)
template<std::integral T>
void TestConcept3(T number)
{
‌cout << number << endl;
}

// 4) Abbreviated Function Template
void TestConcept4(std::integral auto number)
{
‌cout << number << endl;
}


class GameObject
{

};

class Knight : public GameObject
{

};

template<typename T>
requires std::derived_from<T, GameObject>
void TestObj(T* obj)
{

}

template<typename T>
concept MyConcept = !std::is_integral_v<T> && std::derived_from<T, GameObject>;

template<typename T>
concept Addable = requires (T a, T b)
{
‌a + b;
}; // a + b가 가능해야 함

template<typename T>
concept Equality = requires(T a, T b)
{
‌{ a == b } -> std::convertible_to<bool>;
‌{ a != b } -> std::convertible_to<bool>;
};

template<typename T>
concept Integral = std::is_integral_v<T>;

template<typename T>
concept SignedInt = Integral<T> && std::is_signed_v<T>;

int main()
{
‌TestConcept4(10);
‌//TestConcept4(10.3f);
‌//const bool check = _Is_any_of_v<int, short, int, long long>;


‌// 언어 관련
‌// same_as
‌// derived_from
‌// convertible_to
‌// common_reference_with
‌// common_with
‌// assignable_from
‌// swappable

‌// 산술 관련
‌// integral
‌// signed integral
‌// unsigned_integral
‌// floating_point

‌// 생명주기 관련
‌// destructible
‌// constructible_from
‌// default_constructible
‌// move_constructible
‌// copy_constructible

‌// 비교 관련
‌// equality_comparable
‌// totally_ordered

‌// 오브젝트 관련
‌// movable
‌// copyable
‌// semiregular
‌// regular

‌// 호출(Callable) 관련
‌// invocable
‌// regular_invocable
‌// predicate

‌// 반복자 관련
‌// input_iterator
‌// output_iterator
‌// forward_iterator
‌// bidirectional_iterator
‌// random_access_iterator (***)
‌// contiguous_iterator

‌// 알고리즘/범위 관련
‌// permutable
‌// mergeable
‌// sortable
‌// ranges::input_range
‌// ranges::random_access_range
‌// ...

‌//list<int> li;
‌//std::sort(li.begin(), li.end());

‌TestObj(new Knight);
‌//TestObj(new int);

}