function template
<algorithm>
std::find_if_not
template <class InputIterator, class UnaryPredicate>
InputIterator find_if_not (InputIterator first, InputIterator last, UnaryPredicate pred);
Find element in range (negative condition)
Returns an iterator to the first element in the range [first,last)
for which pred returns false
. If no such element is found, the function returns last.
The behavior of this function template is equivalent to:
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template<class InputIterator, class UnaryPredicate>
InputIterator find_if_not (InputIterator first, InputIterator last, UnaryPredicate pred)
{
while (first!=last) {
if (!pred(*first)) return first;
++first;
}
return last;
}
| |
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 is considered a match in the context of this function.
The function shall not modify its argument.
This can either be a function pointer or a function object.
Return value
An iterator to the first element in the range for which pred returns false
.
If pred is true
for all elements, the function returns last.
Example
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// find_if_not example
#include <iostream> // std::cout
#include <algorithm> // std::find_if_not
#include <array> // std::array
int main () {
std::array<int,5> foo = {1,2,3,4,5};
std::array<int,5>::iterator it =
std::find_if_not (foo.begin(), foo.end(), [](int i){return i%2;} );
std::cout << "The first even value is " << *it << '\n';
return 0;
}
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Output:
The first even value is 2
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Complexity
Up to linear in the distance between first and last: Calls pred for each element until a mismatch 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
- find_if
- Find element in range (function template
)
- mismatch
- Return first position where two ranges differ (function template
)
- none_of
- Test if no elements fulfill condition (function template
)