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C++20 Library support for operator<=> <compare>

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Library support for
operator<=>
<compare>
3방향 비교 연산자 (a.k.a 우주선 연산자)
0 : 같음
양수 : 크다
음수 : 작다
<compare> 헤더를 추가해야 사용 가능
단순하고 강력한 비교를 위해 추가 됨
연산자 오버로딩
기존 6개의 비교 연산자
모두 적용됨
default 일 경우 멤버 변수
선언 순서에 따라 비교
연산자 오버로딩
3방향 비교 연산자 반환 타입
3방향 비교 연산자는
strong_ordering, weak_ordering, partial_ordering
중 하나의 타입으로 반환이 됨
~ordering
strong weak partial
less : a < b O O O
equivalent : !(a > b) && !(a < b) ex. insert O O O
equal : a == b ex. find O X X
greater : a > b O O O
unordered : 비교 불가능한 값 지원 ex. Nan X X O
더 강한 순서는 약한 순서로 암묵적 변환이 가능
연산자 오버로딩시 반환 타입을 지정해 줌으로서 어떤
객체인지 알려줄 수도 있다

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C++20 Library support for operator<=> <compare>

  • 2. 3방향 비교 연산자 (a.k.a 우주선 연산자) 0 : 같음 양수 : 크다 음수 : 작다 <compare> 헤더를 추가해야 사용 가능 단순하고 강력한 비교를 위해 추가 됨
  • 3. 연산자 오버로딩 기존 6개의 비교 연산자 모두 적용됨 default 일 경우 멤버 변수 선언 순서에 따라 비교
  • 5. 3방향 비교 연산자 반환 타입 3방향 비교 연산자는 strong_ordering, weak_ordering, partial_ordering 중 하나의 타입으로 반환이 됨
  • 6. ~ordering strong weak partial less : a < b O O O equivalent : !(a > b) && !(a < b) ex. insert O O O equal : a == b ex. find O X X greater : a > b O O O unordered : 비교 불가능한 값 지원 ex. Nan X X O 더 강한 순서는 약한 순서로 암묵적 변환이 가능 연산자 오버로딩시 반환 타입을 지정해 줌으로서 어떤 객체인지 알려줄 수도 있다