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

Defined in header `<algorithm>`
Call signature
template< InputIterator I, Sentinel<I> S, class Proj = std::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > bool all_of( I first, S last, Pred pred, Proj proj = {} );	(1)	(since C++20)
template< InputRange R, class Proj = std::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred > bool all_of( R&& r, Pred pred, Proj proj = {} );	(2)	(since C++20)
template< InputIterator I, Sentinel<I> S, class Proj = std::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > bool any_of( I first, S last, Pred pred, Proj proj = {} );	(3)	(since C++20)
template< InputRange R, class Proj = std::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred > bool any_of( R&& r, Pred pred, Proj proj = {} );	(4)	(since C++20)
template< InputIterator I, Sentinel<I> S, class Proj = std::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > bool none_of( I first, S last, Pred pred, Proj proj = {} );	(5)	(since C++20)
template< InputRange R, class Proj = std::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred > bool none_of( R&& r, Pred pred, Proj proj = {} );	(6)	(since C++20)

1) Checks if unary predicate pred returns true for all elements in the range [first, last) (after projecting with the projection proj).

3) Checks if unary predicate pred returns true for at least one element in the range [first, last) (after projecting with the projection proj).

5) Checks if unary predicate pred returns true for no elements in the range [first, last) (after projecting with the projection proj).

2,4,6) Same as (1,3,5), but uses r as the source range, as if using ranges::begin(r) as first and ranges::end(r) as last.

The function-like entities described on this page are niebloids, that is:

Explicit template argument lists may not be specified when calling any of them.
None of them is visible to argument-dependent lookup.
When one of them is found by normal unqualified lookup for the name to the left of the function-call operator, it inhibits argument-dependent lookup.

In practice, they may be implemented as function objects, or with special compiler extensions.

Parameters

first, last	-	the range of the elements to examine
r	-	the range of the elements to examine
pred	-	predicate to apply to the projected elements
proj	-	projection to apply to the elements

Return value

1-2) true if std::invoke(pred, std::invoke(proj, *i)) != false for every iterator i in the range, false otherwise. Returns true if the range is empty.

3-4) true if std::invoke(pred, std::invoke(proj, *i)) != false for at least one iterator i in the range, false otherwise. Returns false if the range is empty.

5-6) true if std::invoke(pred, std::invoke(proj, *i)) == false for every iterator i in the range, false otherwise. Returns true if the range is empty.

Complexity

At most last - first applications of the predicate and the projection.

Possible implementation

First version
struct all_of_fn { template< InputIterator I, Sentinel<I> S, class Proj = std::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > bool operator()( I first, S last, Pred pred, Proj proj = {} ) const { return ranges::find_if_not(first, last, std::ref(pred), std::ref(proj)) == last; } template< InputRange R, class Proj = std::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred > bool operator()( R&& r, Pred pred, Proj proj = {} ) const { return operator()(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj)); } }; inline constexpr all_of_fn all_of;
Second version
struct any_of_fn { template< InputIterator I, Sentinel<I> S, class Proj = std::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > bool operator()( I first, S last, Pred pred, Proj proj = {} ) const { return ranges::find_if(first, last, std::ref(pred), std::ref(proj)) != last; } template< InputRange R, class Proj = std::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred > bool operator()( R&& r, Pred pred, Proj proj = {} ) const { return operator()(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj)); } }; inline constexpr any_of_fn any_of;
Third version
struct none_of_fn { template< InputIterator I, Sentinel<I> S, class Proj = std::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > bool operator()( I first, S last, Pred pred, Proj proj = {} ) const { return ranges::find_if(first, last, std::ref(pred), std::ref(proj)) == last; } template< InputRange R, class Proj = std::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred > bool operator()( R&& r, Pred pred, Proj proj = {} ) const { return operator()(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj)); } }; inline constexpr none_of_fn none_of;

Example

#include <vector>
#include <numeric>
#include <algorithm>
#include <iterator>
#include <iterator>
#include <iostream>
#include <functional>
 
namespace ranges = std::ranges;
 
int main()
{
    std::vector<int> v(10, 2);
    std::partial_sum(v.cbegin(), v.cend(), v.begin());
    std::cout << "Among the numbers: ";
    ranges::copy(v, std::ostream_iterator<int>(std::cout, " "));
    std::cout << '\n';
 
    if (ranges::all_of(v.cbegin(), v.cend(), [](int i){ return i % 2 == 0; })) {
        std::cout << "All numbers are even\n";
    }
    if (ranges::none_of(v, std::bind(std::modulus<int>(), 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 (ranges::any_of(v, 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