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operator==,!=,<,<=,>,>=(std::pair)

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< cpp‎ | utility‎ | pair

 
 
ユーティリティライブラリ
支援を入力します (basic types, RTTI, type traits)
動的なメモリ管理
エラー処理
プログラムユーティリティ
可変個引数関数
日付と時刻
関数オブジェクト
initializer_list(C++11)
bitset
hash(C++11)
関係演算子
Original:
Relational operators
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rel_ops::operator!=
rel_ops::operator>
rel_ops::operator<=
rel_ops::operator>=
ペアとタプル
Original:
Pairs and tuples
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pair
tuple(C++11)
piecewise_construct_t(C++11)
piecewise_construct(C++11)
フォワード、スワップ、および移動
Original:
Swap, forward and move
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swap
forward(C++11)
move(C++11)
move_if_noexcept(C++11)
declval(C++11)
 
std::pair
メンバ関数
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Member functions
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pair::pair
pair::operator=
pair::swap
非メンバ関数
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Non-member functions
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make_pair
operator=
operator!=
operator<
operator<=
operator>
operator>=
std::swap
get(C++11)
ヘルパークラス
Original:
Helper classes
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tuple_size(C++11)
tuple_element(C++11)
 
Defined in header <utility>
template< class T1, class T2 >
bool operator==( const pair<T1,T2>& lhs, const pair<T1,T2>& rhs );
(1)
template< class T1, class T2 >
bool operator!=( const pair<T1,T2>& lhs, const pair<T1,T2>& rhs );
(2)
template< class T1, class T2 >
bool operator<( const pair<T1,T2>& lhs, const pair<T1,T2>& rhs );
(3)
template< class T1, class T2 >
bool operator<=( const pair<T1,T2>& lhs, const pair<T1,T2>& rhs );
(4)
template< class T1, class T2 >
bool operator>( const pair<T1,T2>& lhs, const pair<T1,T2>& rhs );
(5)
template< class T1, class T2 >
bool operator>=( const pair<T1,T2>& lhs, const pair<T1,T2>& rhs );
(6)

1-2) Tests if both elements of lhs and rhs are equal, that is, compares lhs.first with rhs.first and lhs.second with rhs.second

3-6) Compares lhs and rhs lexicographically, that is, compares the first elements and only if they are equivalent, compares the second elements.

[編集] パラメータ

lhs, rhs - pairs to compare

[編集] 値を返します

1) true if both lhs.first == rhs.first and lhs.second == rhs.second, otherwise false

2) true if either lhs.first != rhs.first or lhs.second != rhs.second, otherwise false

3) If lhs.first<rhs.first, returns true. Otherwise, if rhs.first<lhs.first, returns false. Otherwise, if lhs.second<rhs.second, returns true. Otherwise, returns false.

4) !(rhs < lhs)

5) rhs < lhs

6) !(lhs < rhs)

[編集]

Because operator< is defined for pairs, containers of pairs can be sorted.

#include <iostream>
#include <utility>
#include <vector>
#include <algorithm>
 
int main()
{
    std::vector<std::pair<int, std::string>> v = { {2, "baz"},
                                                   {2, "bar"},
                                                   {1, "foo"} };
    std::sort(v.begin(), v.end());
 
    for(auto p: v) {
        std::cout << "(" << p.first << "," << p.second << ")\n";
    }
}

Output:

(1,foo)
(2,bar)
(2,baz)