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

Template:cpp/algorithm/sidebar Template:ddcl list begin <tr class="t-dsc-header">

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Defined in header <algorithm>

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<td></td> <td></td> </tr> <tr class="t-dcl ">

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template< class InputIterator, class UnaryPredicate >
bool all_of( InputIterator first, InputIterator last, UnaryPredicate p );

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<td > (1) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

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template< class InputIterator, class UnaryPredicate >
bool any_of( InputIterator first, InputIterator last, UnaryPredicate p );

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<td > (2) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

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template< class InputIterator, class UnaryPredicate >
bool none_of( InputIterator first, InputIterator last, UnaryPredicate p );

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<td > (3) </td> <td > (since C++11) </td> </tr> Template:ddcl list end

1) Checks if unary predicate p returns Template:cpp for all elements in the range [first, last).

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

3) Checks if unary predicate p returns Template:cpp for no elements in the range [first, last).

Parameters

first, last	-	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 InputIterator, 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). ​

Return value

1) Template:cpp if unary predicate returns Template:cpp for all elements in the range, Template:cpp otherwise. Returns Template:cpp if the range is empty.

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

3) Template:cpp if unary predicate returns Template:cpp for no elements in the range, Template:cpp otherwise. Returns Template:cpp if the range is empty.

Complexity

At most last - first applications of the predicate

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.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 (std::none_of(v.begin(), v.end(), std::bind(std::modulus<int>(), 
                                                   std::placeholder::_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