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std::all_of, std::any_of, std::none_of

Defined in header <algorithm>
(1)
template< class InputIt, class UnaryPredicate >
bool all_of( InputIt first, InputIt last, UnaryPredicate p );
(since C++11)
(until C++20)
template< class InputIt, class UnaryPredicate >
constexpr bool all_of( InputIt first, InputIt last, UnaryPredicate p );
(since C++20)
template< class ExecutionPolicy, class ForwardIt, class UnaryPredicate >
bool all_of( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last,
             UnaryPredicate p );
(2) (since C++17)
(3)
template< class InputIt, class UnaryPredicate >
bool any_of( InputIt first, InputIt last, UnaryPredicate p );
(since C++11)
(until C++20)
template< class InputIt, class UnaryPredicate >
constexpr bool any_of( InputIt first, InputIt last, UnaryPredicate p );
(since C++20)
template< class ExecutionPolicy, class ForwardIt, class UnaryPredicate >
bool any_of( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last,
             UnaryPredicate p );
(4) (since C++17)
(5)
template< class InputIt, class UnaryPredicate >
bool none_of( InputIt first, InputIt last, UnaryPredicate p );
(since C++11)
(until C++20)
template< class InputIt, class UnaryPredicate >
constexpr bool none_of( InputIt first, InputIt last, UnaryPredicate p );
(since C++20)
template< class ExecutionPolicy, class ForwardIt, class UnaryPredicate >
bool none_of( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last,
              UnaryPredicate p );
(6) (since C++17)
1) Checks if unary predicate p returns true for all elements in the range [firstlast).
3) Checks if unary predicate p returns true for at least one element in the range [firstlast).
5) Checks if unary predicate p returns true for no elements in the range [firstlast).
2,4,6) Same as (1,3,5), but executed according to policy. These overloads do not participate in overload resolution unless

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 v of type (possibly const) VT, where VT is the value type of InputIt, regardless of value category, and must not modify v. Thus, a parameter type of VT&is not allowed, nor is VT unless for VT a move is equivalent to a copy (since C++11). ​

Type requirements
-InputIt must meet the requirements of LegacyInputIterator.
-ForwardIt must meet the requirements of LegacyForwardIterator.
-UnaryPredicate must meet the requirements of Predicate.

Return value

1-2) true if unary predicate returns true for all elements in the range, false otherwise. Returns true if the range is empty.
3-4) true if unary predicate returns true for at least one element in the range, false otherwise. Returns false if the range is empty.
5-6) true if unary predicate returns true for no elements in the range, false otherwise. Returns true if the range is empty.

See also Notes below.

Complexity

1,3,5) At most last - first applications of the predicate
2,4,6) O(last - first) applications of the predicate

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 other ExecutionPolicy, 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 UnaryPredicate>
constexpr bool all_of(InputIt first, InputIt last, UnaryPredicate p)
{
    return std::find_if_not(first, last, p) == last;
}
any_of
template<class InputIt, class UnaryPredicate>
constexpr bool any_of(InputIt first, InputIt last, UnaryPredicate p)
{
    return std::find_if(first, last, p) != last;
}
none_of
template<class InputIt, class UnaryPredicate>
constexpr bool none_of(InputIt first, InputIt last, UnaryPredicate p)
{
    return std::find_if(first, last, p) == last;
}

Notes

The return value represented in the form of the Truth table is:

input range contains
all true,
none false
some true,
some false
none true,
all false
none true,
none false
(empty range)
1–2) all_of true false false true
3–4) any_of true true false false
5–6) none_of false false true true

Example

#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)

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