Difference between revisions of "cpp/algorithm/all any none of"

Revision as of 15:24, 19 April 2012

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

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

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

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

<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

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

Possible implementation

Template:eq fun cpp

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 (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";
    }
}

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