std::all_of, std::any_of, std::none_of
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)
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 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
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
-
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
See also the implementations of
| 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 <algorithm>
#include <functional>
#include <iostream>
#include <iterator>
#include <numeric>
#include <vector>
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
[edit] See also
checks if a predicate is
true for all, any or none of the elements in a range
(algorithm function object)[edit]