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

From cppreference.com
< 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 parallelism 2 (parallelism TS v2)
Extensions for concurrency (concurrency TS)
Concepts (concepts TS)
Ranges (ranges TS)
Mathematical special functions (special functions TR)
 
 
 
template< InputIterator I, Sentinel<I> S, class Proj = ranges::identity,

          IndirectUnaryPredicate<projected<I, Proj>> Pred >

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

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

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

          IndirectUnaryPredicate<projected<I, Proj>> Pred >

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

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

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

          IndirectUnaryPredicate<projected<I, Proj>> Pred >

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

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

bool none_of( R&& r, 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 r as the source range, as if using ranges::begin(r) as first and ranges::end(r) as last.

Notwithstanding the declarations depicted above, the actual number and order of template parameters for algorithm declarations is unspecified. Thus, if explicit template arguments are used when calling an algorithm, the program is probably non-portable.

Contents

[edit] 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

[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< InputIterator I, Sentinel<I> S, class Proj = ranges::identity,
          IndirectUnaryPredicate<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< InputRange R, class Proj = ranges::identity,
          IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred >
bool all_of( R&& r, Pred pred, Proj proj = Proj{} )
{
   return ranges::all_of(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj));
}
Second version
template< InputIterator I, Sentinel<I> S, class Proj = ranges::identity,
          IndirectUnaryPredicate<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< InputRange R, class Proj = ranges::identity,
         IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred >
bool any_of( R&& r, Pred pred, Proj proj = Proj{} )
{
   return ranges::any_of(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj));
}
Third version
template< InputIterator I, Sentinel<I> S, class Proj = identity,
          IndirectUnaryPredicate<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< InputRange R, class Proj = ranges::identity,
          IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred >
bool none_of( R&& r, Pred pred, Proj proj = Proj{} )
{
   return ranges::none_of(ranges::begin(r), ranges::end(r), 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

(C++11)(C++11)(C++11)
checks if a predicate is true for all, any or none of the elements in a range
(function template) [edit]