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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 [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 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.

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

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