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find_if
function template
<algorithm>
template <class InputIterator, class Predicate>
InputIterator find_if ( InputIterator first, InputIterator last, Predicate pred );
Find element in range
Returns an iterator to the first element in the range [first,last) for which applying pred to it, is true.
The behavior of this function template is equivalent to:
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template<class InputIterator, class Predicate>
InputIterator find_if ( InputIterator first, InputIterator last, Predicate pred )
{
for ( ; first!=last ; first++ ) if ( pred(*first) ) break;
return first;
}
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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 predicate taking an element in the range as argument, and returning a value indicating the falsehood (with false, or a zero value) or truth (true, or non-zero) of some condition applied to it. This can either be a pointer to a function or an object whose class overloads operator().
Return value
An iterator to the first element in the range for which the application of pred to it does not return false (zero).
If pred is false for all elements, the function returns last.
Example
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// find_if example
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
bool IsOdd (int i) {
return ((i%2)==1);
}
int main () {
vector<int> myvector;
vector<int>::iterator it;
myvector.push_back(10);
myvector.push_back(25);
myvector.push_back(40);
myvector.push_back(55);
it = find_if (myvector.begin(), myvector.end(), IsOdd);
cout << "The first odd value is " << *it << endl;
return 0;
}
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Output:
The first odd value is 25
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Complexity
At most, performs as many applications of pred as the number of elements in the range [first,last).
See also
| find | Find value in range (function template) |
| for_each | Apply function to range (template function) |
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