std::all_of, std::any_of, std::none_of
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(Redirected from cpp/algorithm/any of)
| Defined in header <algorithm>
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template< class InputIt, class UnaryPred > bool all_of( InputIt first, InputIt last, UnaryPred p ); |
(1) | (since C++11) (constexpr since C++20) |
template< class ExecutionPolicy, class ForwardIt, class UnaryPred > bool all_of( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last, UnaryPred p ); |
(2) | (since C++17) |
template< class InputIt, class UnaryPred > bool any_of( InputIt first, InputIt last, UnaryPred p ); |
(3) | (since C++11) (constexpr since C++20) |
template< class ExecutionPolicy, class ForwardIt, class UnaryPred > bool any_of( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last, UnaryPred p ); |
(4) | (since C++17) |
template< class InputIt, class UnaryPred > bool none_of( InputIt first, InputIt last, UnaryPred p ); |
(5) | (since C++11) (constexpr since C++20) |
template< class ExecutionPolicy, class ForwardIt, class UnaryPred > bool none_of( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last, UnaryPred p ); |
(6) | (since C++17) |
1) Checks if unary predicate
p returns true for all elements in the range [first, last).3) Checks if unary predicate
p returns true for at least one element in the range [first, last).5) Checks if unary predicate
p returns true for none of the elements in the range [first, last).2,4,6) Same as (1,3,5), but executed according to
policy. These overloads participate in overload resolution only if all following conditions are satisfied:
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(until C++20) |
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(since C++20) |
Parameters
| first, last | - | the pair of iterators defining the range of elements to examine |
| policy | - | the execution policy to use |
| p | - | unary predicate . The expression |
| Type requirements | ||
-InputIt must meet the requirements of LegacyInputIterator.
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-ForwardIt must meet the requirements of LegacyForwardIterator.
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-UnaryPred must meet the requirements of Predicate.
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Return value
Range has some true element
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Yes | No | ||
|---|---|---|---|---|
Range has some false element
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Yes | No | Yes | No[1] |
all_of
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false
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true
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false
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true
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any_of
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true
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true
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false
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false
|
none_of
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false
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false
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true
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true
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- ↑ The range is empty in this case.
Complexity
1-6) At most
std::distance(first, last) applications of the predicate p.Exceptions
The overloads with a template parameter named ExecutionPolicy report errors as follows:
- If execution of a function invoked as part of the algorithm throws an exception and
ExecutionPolicyis one of the standard policies, std::terminate is called. For any otherExecutionPolicy, the behavior is implementation-defined. - If the algorithm fails to allocate memory, std::bad_alloc is thrown.
Possible implementation
See also the implementations of
| all_of |
|---|
template<class InputIt, class UnaryPred>
constexpr bool all_of(InputIt first, InputIt last, UnaryPred p)
{
return std::find_if_not(first, last, p) == last;
}
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| any_of |
template<class InputIt, class UnaryPred>
constexpr bool any_of(InputIt first, InputIt last, UnaryPred p)
{
return std::find_if(first, last, p) != last;
}
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| none_of |
template<class InputIt, class UnaryPred>
constexpr bool none_of(InputIt first, InputIt last, UnaryPred p)
{
return std::find_if(first, last, p) == last;
}
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Example
Run this code
#include <algorithm>
#include <functional>
#include <iostream>
#include <iterator>
#include <numeric>
#include <vector>
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<>(),
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
See also
(C++20)(C++20)(C++20) |
checks if a predicate is true for all, any or none of the elements in a range(algorithm function object) |