function template
<algorithm>

std::any_of

template <class InputIterator, class UnaryPredicate>
  bool any_of (InputIterator first, InputIterator last, UnaryPredicate pred);
Test if any element in range fulfills condition
Returns true if pred returns true for any of the elements in the range [first,last), and false otherwise.

If [first,last) is an empty range, the function returns false.

The behavior of this function template is equivalent to:
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template<class InputIterator, class UnaryPredicate>
  bool any_of (InputIterator first, InputIterator last, UnaryPredicate pred)
{
  while (first!=last) {
    if (pred(*first)) return true;
    ++first;
  }
  return false;
}


Parameters

first, last
Input iterators to the initial and final positions in a sequence. The range used is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
pred
Unary function that accepts an element in the range as argument and returns a value convertible to bool. The value returned indicates whether the element fulfills the condition checked by this function.
The function shall not modify its argument.
This can either be a function pointer or a function object.

Return value

true if pred returns true for any of the elements in the range [first,last), and false otherwise.

If [first,last) is an empty range, the function returns false.

Example

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// any_of example
#include <iostream>     // std::cout
#include <algorithm>    // std::any_of
#include <array>        // std::array

int main () {
  std::array<int,7> foo = {0,1,-1,3,-3,5,-5};

  if ( std::any_of(foo.begin(), foo.end(), [](int i){return i<0;}) )
    std::cout << "There are negative elements in the range.\n";

  return 0;
}


Output:
There are negative elements in the range.

Complexity

Up to linear in the distance between first and last: Calls pred for each element until a match is found.

Data races

Some (or all) of the objects in the range [first,last) are accessed (once at most).

Exceptions

Throws if either pred or an operation on an iterator throws.
Note that invalid parameters cause undefined behavior.

See also

all_of
Test condition on all elements in range (function template )
none_of
Test if no elements fulfill condition (function template )
find_if
Find element in range (function template )

C++