std::all_of, std::any_of, std::none_of
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| Defined in header <algorithm>
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| template< class InputIt, class UnaryPredicate > bool all_of( InputIt first, InputIt last, UnaryPredicate p ); |
(1) | (C++11 起) |
| template< class InputIt, class UnaryPredicate > bool any_of( InputIt first, InputIt last, UnaryPredicate p ); |
(2) | (C++11 起) |
| template< class InputIt, class UnaryPredicate > bool none_of( InputIt first, InputIt last, UnaryPredicate p ); |
(3) | (C++11 起) |
一元谓词检查是否
2) p回报true范围内的所有元素[first, last).Original:
Checks if unary predicate
p returns true for all elements in the range [first, last).The text has been machine-translated via Google Translate.
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一元谓词检查是否
3) p回报true的范围内至少有一个元素[first, last).Original:
Checks if unary predicate
p returns true for at least one element in the range [first, last).The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
一元谓词检查是否
p回报true的范围内没有任何元素[first, last).Original:
Checks if unary predicate
p returns true for no elements in the range [first, last).The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
目录 |
[编辑] 参数
| first, last | - | 检查的元素
Original: the range of elements to examine The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. | |||||||||
| p | - | unary predicate . The signature of the predicate function should be equivalent to the following:
The signature does not need to have const &, but the function must not modify the objects passed to it. | |||||||||
| Type requirements | |||||||||||
-InputIt must meet the requirements of InputIterator.
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[编辑] 返回值
1)true如果一元谓词返回true范围内的所有元素,false不然。返回true的范围内是空
2) Original:
true if unary predicate returns true for all elements in the range, false otherwise. Returns true if the range is empty.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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true如果一元谓词返回true的范围内至少有一个元素,false不然。返回false的范围内是空
3) Original:
true if unary predicate returns true for at least one element in the range, false otherwise. Returns false if the range is empty.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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true如果一元谓词返回true的范围内没有任何元素,false不然。返回true的范围内是空
Original:
true if unary predicate returns true for no elements in the range, false otherwise. Returns true if the range is empty.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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[编辑] 复杂性
在最
last - first谓词的应用Original:
At most
last - first applications of the predicateThe text has been machine-translated via Google Translate.
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[编辑] 可能的实现
| First version |
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template< class InputIt, class UnaryPredicate > bool all_of(InputIt first, InputIt last, UnaryPredicate p) { for (; first != last; ++first) { if (!p(*first)) return false; } return true; } |
| Second version |
template< class InputIt, class UnaryPredicate > bool any_of(InputIt first, InputIt last, UnaryPredicate p) { for (; first != last; ++first) { if (p(*first)) return true; } return false; } |
| Third version |
template< class InputIt, class UnaryPredicate > bool none_of(InputIt first, InputIt last, UnaryPredicate p) { for (; first != last; ++first) { if (p(*first)) return false; } return true; } |
[编辑] 为例
#include <vector> #include <numeric> #include <algorithm> #include <iterator> #include <iostream> #include <functional> int main() { std::vector<int> v(10, 2); std::partial_sum(v.cbegin(), v.cend(), v.begin()); std::cout << "Among the numbers: "; std::copy(v.cbegin(), v.cend(), std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n'; if (std::all_of(v.cbegin(), v.cend(), [](int i){ return i % 2 == 0; })) { std::cout << "All numbers are even\n"; } if (std::none_of(v.cbegin(), v.cend(), std::bind(std::modulus<int>(), std::placeholders::_1, 2))) { std::cout << "None of them are odd\n"; } struct DivisibleBy { const int d; DivisibleBy(int n) : d(n) {} bool operator()(int n) const { return n % d == 0; } }; if (std::any_of(v.cbegin(), v.cend(), DivisibleBy(7))) { std::cout << "At least one number is divisible by 7\n"; } }
Output:
Among the numbers: 2 4 6 8 10 12 14 16 18 20 All numbers are even None of them are odd At least one number is divisible by 7