C++ 템플릿 - Concept

Concept

• C++20
• 템플릿 파라미터에 제약조건을 추가
• g++ concept.cpp -fconcepts

struct Point
{
	int x, y;
	bool operator<(const Point& p) { return true; }
};

// concept 생성
template<typename T>
concept bool LessThanComparable = requires(T a, T b)
{
	{ a < b } -> bool;
};

// template 뒤에 붙이기
template<typename T> requires LessThanComparable<T>
T Min1(T a, T b)
{
	return a < b ? a : b;
}

// 함수선언 뒤에 붙이기
template<typename T>
T Min2(T a, T b) requires LessThanComparable<T>
{
	return a < b ? a : b;
}

// template 없이...
LessThanCompareable Min3(LessThanComparable a, LessThanComparable b)
{
	return a < b ? a : b
}

int main()
{
	Point p1, p2;
	Min(p1, p2);
}