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

From Cppreference

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).

[edit] Parameters

[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

template< class InputIterator, class UnaryPredicate >
bool all_of(InputIterator first, InputIterator last, UnaryPredicate p)
{
    for (; first != last; ++first) {
        if (!p(*first)) return false;
    }
    return true;
}

template< class InputIterator, class UnaryPredicate >
bool any_of(InputIterator first, InputIterator last, UnaryPredicate p)
{
    for (; first != last; ++first) {
        if (p(*first)) return true;
    }
    return false;
}

template< class InputIterator, class UnaryPredicate >
bool none_of(InputIterator first, InputIterator last, UnaryPredicate p)
{
    for (; first != last; ++first) {
        if (p(*first)) return false;
    }
    return true;
}

[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