std::find, std::find_if, std::find_if_not
Defined in header <algorithm> | ||
template<class InputIt, class T > InputIt find( InputIt first, InputIt last, const T& value ); | (1) | |
template<class InputIt, class UnaryPredicate > InputIt find_if( InputIt first, InputIt last, | (2) | |
template<class InputIt, class UnaryPredicate > InputIt find_if_not( InputIt first, InputIt last, | (3) | (C++11およびそれ以降) |
これらの関数は、特定の条件を満たす範囲[first, last)内の最初の要素を見つけます。
1. find は値valueに等しい要素を検索します。
2. find_if は述語pの戻り値がtrueの要素を検索します。
3. find_if_not は述語qの戻り値がfalseの要素を検索します。
目次 |
[編集]パラメータ
| first, last | - | 検索する要素の範囲 |
| value | - | 要素と比較する値 |
| p | - | unary predicate which returns true 必須要素のために. The signature of the predicate function should be equivalent to the following: bool pred(const Type &a); The signature does not need to have const&, but the function must not modify the objects passed to it. |
| q | - | unary predicate which returns false 必須要素のために. The signature of the predicate function should be equivalent to the following: bool pred(const Type &a); The signature does not need to have const&, but the function must not modify the objects passed to it. |
| 型の要件 | ||
-InputIt は InputIteratorの要求を満足しなければなりません。 | ||
[編集]返り値
条件を満たす最初の要素へのイテレータ。そのような要素がみつからない場合はlast
[編集]計算複雑性
せいぜいlast - 述語のfirstアプリケーション
[編集]可能な実装
| First version |
|---|
template<class InputIt, class T> InputIt find(InputIt first, InputIt last, const T& value){for(; first != last;++first){if(*first == value){return first;}}return last;} |
| Second version |
template<class InputIt, class UnaryPredicate> InputIt find_if(InputIt first, InputIt last, UnaryPredicate p){for(; first != last;++first){if(p(*first)){return first;}}return last;} |
| Third version |
template<class InputIt, class UnaryPredicate> InputIt find_if_not(InputIt first, InputIt last, UnaryPredicate q){for(; first != last;++first){if(!q(*first)){return first;}}return last;} |
You can help to correct and verify the translation. Click here for instructions.
template<class InputIt, class UnaryPredicate> InputIt find_if_not(InputIt first, InputIt last, UnaryPredicate q){return std::find_if(first, last, std::not1(q));} |
[編集]例
You can help to correct and verify the translation. Click here for instructions.
#include <iostream>#include <algorithm>#include <vector> int main(){int n1 =3;int n2 =5; std::vector<int> v{0, 1, 2, 3, 4}; auto result1 = std::find(v.begin(), v.end(), n1);auto result2 = std::find(v.begin(), v.end(), n2); if(result1 != v.end()){std::cout<<"v contains: "<< n1 <<'\n';}else{std::cout<<"v does not contain: "<< n1 <<'\n';} if(result2 != v.end()){std::cout<<"v contains: "<< n2 <<'\n';}else{std::cout<<"v does not contain: "<< n2 <<'\n';}}
出力:
v contains: 3 v does not contain: 5
[編集]参考
互いに隣接する2つの同一の（またはいくつかの他の関係）のアイテムを見つけることができます Original: finds two identical (or some other relationship) items adjacent to each other The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (関数テンプレート) | |
一定の範囲内にある要素の最後のシーケンスを見つけることができます Original: finds the last sequence of elements in a certain range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (関数テンプレート) | |
| searches for any one of a set of elements (関数テンプレート) | |
2の範囲が異なる最初の位置を見つけます Original: finds the first position where two ranges differ The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (関数テンプレート) | |
| ある範囲の要素を検索します (関数テンプレート) | |
