C++ Algorithm Library - find_end() Function

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Description

The C++ function std::algorithm::find_end() finds the last occurrence of the element. It uses operator = for comparison.

Declaration

Following is the declaration for std::algorithm::find_end() function form std::algorithm header.

C++98

template <class ForwardIterator1, class ForwardIterator2>
ForwardIterator1 find_end(ForwardIterator1 first1, ForwardIterator1 last1,
   ForwardIterator2 first2, ForwardIterator2 last2);

Parameters

• first1 − Forward iterator to the initial position of the first sequence.

• last1 − Forward iterator to the final position of the first sequence.

• first2 − Forward iterator to the initial position of the second sequence.

• last2 − Forward iterator to the final position of the second sequence.

Return value

Returns an iterator to the first element of the last occurrence of (first2,last2) in first1,last1.

Exceptions

Throws exception if either element comparison or an operation on an iterator throws exception.

Please note that invalid parameters cause undefined behavior.

Time complexity

Linear.

Example

The following example shows the usage of std::algorithm::find_end() function.

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main(void) {
   vector<int> v1 = {1, 2, 1, 2, 1, 2};
   vector<int> v2 = {1, 2};

   auto result = find_end(v1.begin(), v1.end(), v2.begin(), v2.end());

   if (result != v1.end())
      cout << "Last sequence found at location "
         << distance(v1.begin(), result) << endl;

   v2 = {1, 3};

   result = find_end(v1.begin(), v1.end(), v2.begin(), v2.end());

   if (result == v1.end())
      cout << "Sequence doesn't present in vector." << endl;

   return 0;
}

Let us compile and run the above program, this will produce the following result −

Last sequence found at location 4
Sequence doesn't present in vector.