◐ Shell
clean mode source ↗

std::all_of, std::any_of, std::none_of - cppreference.com

From cppreference.com

Defined in header <algorithm> 

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

2) Checks if unary predicate p returns true for at least one element in the range [first, last).

3) Checks if unary predicate p returns true for none of the elements in the range [first, last).

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

These overloads participate in overload resolution only if the value of the following expression is true:

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)

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.

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
  1. ↑ The range is empty in this case.

Complexity

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

Exceptions

4-6) During the execution process:

  • If the temporary memory resources required for parallelization are not available, std::bad_alloc is thrown.
  • If an uncaught exception is thrown while accessing objects via an algorithm argument, the behavior is determined by the execution policy (for standard policies, std::terminate is invoked).

Notes

Feature-test macro Value Std Feature
__cpp_lib_parallel_algorithm 202506L (C++26) Parallel range algorithms, (4-6)

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;
}

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";
    
    using namespace std::placeholders;
    if (std::none_of(v.cbegin(), v.cend(), std::bind(std::modulus<>(), _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