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

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< cpp‎ | experimental‎ | ranges
 
 
Technical specifications
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals 2 TS)
Extensions for parallelism (parallelism TS)
Extensions for concurrency (concurrency TS)
Concepts (concepts TS)
Ranges (ranges TS)
Special mathematical functions (special math TR)
 
 
 
template< ranges::InputIterator I, ranges::Sentinel<I> S, class Proj = ranges::identity,

   ranges::IndirectUnaryPredicate<ranges::projected<I, Proj>> Pred >

bool all_of( I first, S last, Pred pred, Proj proj = Proj{} );
(1) (ranges TS)
template< ranges::InputRange Rng, class Proj = ranges::identity,

   ranges::IndirectUnaryPredicate<ranges::projected<ranges::iterator_t<Rng>, Proj>> Pred >

bool all_of( Rng&& rng, Pred pred, Proj proj = Proj{} );
(2) (ranges TS)
template< ranges::InputIterator I, ranges::Sentinel<I> S, class Proj = ranges::identity,

   ranges::IndirectUnaryPredicate<ranges::projected<I, Proj>> Pred >

bool any_of( I first, S last, Pred pred, Proj proj = Proj{} );
(3) (ranges TS)
template< ranges::InputRange Rng, class Proj = ranges::identity,

   ranges::IndirectUnaryPredicate<ranges::projected<ranges::iterator_t<Rng>, Proj>> Pred >

bool any_of( Rng&& rng, Pred pred, Proj proj = Proj{} );
(4) (ranges TS)
template< ranges::InputIterator I, ranges::Sentinel<I> S, class Proj = identity,

   ranges::IndirectUnaryPredicate<ranges::projected<I, Proj>> Pred >

bool none_of( I first, S last, Pred pred, Proj proj = Proj{} );
(5) (ranges TS)
template< ranges::InputRange Rng, class Proj = ranges::identity,

   ranges::IndirectUnaryPredicate<ranges::projected<ranges::iterator_t<Rng>, Proj>> Pred >

bool none_of( Rng&& rng, Pred pred, Proj proj = Proj{} );
(6) (ranges TS)
1) Checks if unary predicate pred returns true for all elements in the range [first, last).
3) Checks if unary predicate pred returns true for at least one element in the range [first, last).
5) Checks if unary predicate pred returns true for no elements in the range [first, last).
2,4,6) Same as (1,3,5), but uses rng as the source range, as if by using ranges::begin(rng) and ranges::end(rng).

Contents

[edit] Parameters

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

[edit] Return value

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

[edit] Complexity

1-6-) At most last - first applications of the predicate and last - first applications of the projection.

[edit] Possible implementation

First version
template< ranges::InputIterator I, ranges::Sentinel<I> S, class Proj = ranges::identity,
   ranges::IndirectUnaryPredicate<ranges::projected<I, Proj>> Pred >
bool all_of( I first, S last, Pred pred, Proj proj = Proj{} )
{
   return ranges::find_if_not(first, last, std::ref(pred), std::ref(proj)) == last;
}
 
template< ranges::InputRange Rng, class Proj = ranges::identity,
   ranges::IndirectUnaryPredicate<ranges::projected<ranges::iterator_t<Rng>, Proj>> Pred >
bool all_of( Rng&& rng, Pred pred, Proj proj = Proj{} )
{
   return ranges::all_of(ranges::begin(rng), ranges::end(rng), std::ref(pred), std::ref(proj));
}
Second version
template< ranges::InputIterator I, ranges::Sentinel<I> S, class Proj = ranges::identity,
   ranges::IndirectUnaryPredicate<ranges::projected<I, Proj>> Pred >
bool any_of( I first, S last, Pred pred, Proj proj = Proj{} )
{
   return ranges::find_if(first, last, std::ref(pred), std::ref(proj)) != last;
}
 
template< ranges::InputRange Rng, class Proj = ranges::identity,
   ranges::IndirectUnaryPredicate<ranges::projected<ranges::iterator_t<Rng>, Proj>> Pred >
bool any_of( Rng&& rng, Pred pred, Proj proj = Proj{} )
{
   return ranges::any_of(ranges::begin(rng), ranges::end(rng), std::ref(pred), std::ref(proj));
}
Third version
template< ranges::InputIterator I, ranges::Sentinel<I> S, class Proj = identity,
   ranges::IndirectUnaryPredicate<ranges::projected<I, Proj>> Pred >
bool none_of( I first, S last, Pred pred, Proj proj = Proj{} )
{
   return ranges::find_if(first, last, std::ref(pred), std::ref(proj)) == last;
}
 
template< ranges::InputRange Rng, class Proj = ranges::identity,
   ranges::IndirectUnaryPredicate<ranges::projected<ranges::iterator_t<Rng>, Proj>> Pred >
bool none_of( Rng&& rng, Pred pred, Proj proj = Proj{} )
{
   return ranges::none_of(ranges::begin(rng), ranges::end(rng), std::ref(pred), std::ref(proj));
}

[edit] Example

#include <vector>
#include <numeric>
#include <experimental/ranges/algorithm>
#include <experimental/ranges/iterator>
#include <iterator>
#include <iostream>
#include <functional>
 
namespace ranges = std::experimental::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, ranges::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

[edit] See also