std::all_of, std::any_of, std::none_of - cppreference.com (original) (raw)

Defined in header
template< class InputIt, class UnaryPred > bool all_of( InputIt first, InputIt last, UnaryPred p );	(1)	(since C++11) (constexpr since C++20)
template< class ExecutionPolicy, class ForwardIt, class UnaryPred > bool all_of( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last, UnaryPred p );	(2)	(since C++17)
template< class InputIt, class UnaryPred > bool any_of( InputIt first, InputIt last, UnaryPred p );	(3)	(since C++11) (constexpr since C++20)
template< class ExecutionPolicy, class ForwardIt, class UnaryPred > bool any_of( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last, UnaryPred p );	(4)	(since C++17)
template< class InputIt, class UnaryPred > bool none_of( InputIt first, InputIt last, UnaryPred p );	(5)	(since C++11) (constexpr since C++20)
template< class ExecutionPolicy, class ForwardIt, class UnaryPred > bool none_of( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last, UnaryPred p );	(6)	(since C++17)

Checks if unary predicate p returns true for all elements in the range [first, last).
Checks if unary predicate p returns true for at least one element in the range [first, last).
Checks if unary predicate p returns true for none of the elements in the range [first, last).

2,4,6) Same as (1,3,5), but executed according to policy.

These overloads participate in overload resolution only if all following conditions are satisfied:

[edit] Parameters

first, last	-	the pair of iterators defining the range of elements to examine
policy	-	the execution policy to use
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.
-UnaryPred must meet the requirements of Predicate.

[edit] Return value

Range has some true element	Yes	No
Range has some false element	Yes	No	Yes	No[1]
all_of	false	true	false	true
any_of	true	true	false	false
none_of	false	false	true	true

↑ The range is empty in this case.

[edit] Complexity

1-6) At most std::distance(first, last) applications of the predicate p.

[edit] 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.

[edit] Possible implementation

all_of
template<class InputIt, class UnaryPred> constexpr bool all_of(InputIt first, InputIt last, UnaryPred p) { return std::find_if_not(first, last, p) == last; }
any_of
template<class InputIt, class UnaryPred> constexpr bool any_of(InputIt first, InputIt last, UnaryPred p) { return std::find_if(first, last, p) != last; }
none_of
template<class InputIt, class UnaryPred> constexpr bool none_of(InputIt first, InputIt last, UnaryPred p) { return std::find_if(first, last, p) == last; }

[edit] Example

#include #include #include #include #include #include int main() { std::vector 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(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