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>> (until C++20) std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>> (since C++20) is true.

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

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 in libstdc++ and libc++.

See also the implementations of any_of in libstdc++ and libc++.

See also the implementations of none_of in libstdc++ and libc++.

First version
template< class InputIt, class UnaryPredicate > constexpr bool all_of(InputIt first, InputIt last, UnaryPredicate p) { return std::find_if_not(first, last, p) == last; }
Second version
template< class InputIt, class UnaryPredicate > constexpr bool any_of(InputIt first, InputIt last, UnaryPredicate p) { return std::find_if(first, last, p) != last; }
Third version
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

Run this code

#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<>(), 
                                                     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

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