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

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Defined in header <algorithm>

template< class InputIterator, class UnaryPredicate >
bool all_of( InputIterator first, InputIterator last, UnaryPredicate p );
(1) (C++11 feature)
template< class InputIterator, class UnaryPredicate >
bool any_of( InputIterator first, InputIterator last, UnaryPredicate p );
(2) (C++11 feature)
template< class InputIterator, class UnaryPredicate >
bool none_of( InputIterator first, InputIterator last, UnaryPredicate p );
(3) (C++11 feature)

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 no elements in the range [first, last).

Contents

[edit] Parameters

first, last - the range of elements to examine
p - unary predicate .

The signature of the predicate function should be equivalent to the following:

bool pred(const Type &a);

The signature does not need to have const &, but the function must not modify the objects passed to it.
The type Type must be such that an object of type InputIterator can be dereferenced and then implicitly converted to Type. ​

[edit] Return value

1) true if unary predicate returns true for all elements in the range, false otherwise. Returns true if the range is empty.

2) true if unary predicate returns true for at least one element in the range, false otherwise. Returns false if the range is empty.

3) true if unary predicate returns true for no elements in the range, false otherwise. Returns true if the range is empty.

[edit] Complexity

At most last - first applications of the predicate

[edit] Equivalent function

[edit] Example

#include <vector>
#include <numeric>
#include <algorithm>
#include <iterator>
#include <iostream>
#include <functional>
 
int main()
{
    std::vector<int> v(10, 2);
    std::partial_sum(v.begin(), v.end(), v.begin());
    std::cout << "Among the numbers: ";
    std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " "));
 
    if (std::all_of(v.begin(), v.end(), [](int i){ return i % 2==0; })) {
        std::cout << "\nAll numbers are even\n";
    }
    if (none_of(v.begin(), v.end(), std::bind(std::modulus<int>(), _1, 2))) {
        std::cout << "None of them are odd\n";
    }
    struct DivisibleBy
    {
        int d;
        DivisibleBy(int n) : d(n) {}
        bool operator()(int n) const { return n % d == 0; }
    };
 
    if( std::any_of(v.begin(), v.end(), 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