std::all_of, std::any_of, std::none_of
From cppreference.com
Defined in header <algorithm>
|
||
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, |
(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, |
(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, |
(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 no 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
std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true. |
(until C++20) |
std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>> is true. |
(since C++20) |
Parameters
first, last | - | the range of elements to examine |
policy | - | the execution policy to use. See execution policy for details. |
p | - | unary predicate . The expression p(v) must be convertible to bool for every argument |
Type requirements | ||
-InputIt must meet the requirements of LegacyInputIterator.
| ||
-ForwardIt must meet the requirements of LegacyForwardIterator.
| ||
-UnaryPred must meet the requirements of Predicate.
|
Return value
Has true element | Yes | No | ||
---|---|---|---|---|
Has false element | Yes | No | Yes | No |
all_of
|
false | true | false | true |
any_of
|
true | true | false | false |
none_of
|
false | false | true | true |
Complexity
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
ExecutionPolicy
is 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; } |
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; } |
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; } |
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 (niebloid) |