NAME

std::all_of,std::any_of,std::none_of - std::all_of,std::any_of,std::none_of

Synopsis

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

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.
unary predicate .

The expression p(v) must be convertible to bool for every argument v
p - 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

See also Notes below.

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

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, some true, none true, none true,
none false some false all false 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

See also

ranges::all_of
ranges::any_of checks if a predicate is true for all, any or none of the elements
ranges::none_of in a range
(C++20) (niebloid)
(C++20)
(C++20)