The C++ copy_backward function is employed to duplicate elements in a reversed sequence, taking in three parameters to copy elements within the [first, last] range. The duplication process initiates in reverse sequence with the endpoint set at 'result'.
Syntax
template<class BidirectionalIterator1, class BidirectionalIterator2>
BidirectionalIterator2 copy_backward(BidirectionalIterator1 first, BidirectionalIterator1 last, BidirectionalIterator2 result);
Parameter
It serves as a bidirectional iterator pointing to the initial element within the range, with the element itself being encompassed within the range.
The ## Parameter iterator points to the final element in the range, excluding the element itself within the range.
It serves as a bidirectional iterator pointing to the ultimate location of the duplicated elements.
Return value
The function provides an iterator for the initial element in a series of duplicated items.
Example 1
#include <iostream>
#include <algorithm>
#include <vector>
int main ()
{ std::vector<int> newvector;
for (int k=1; k<=5; k++)
newvector.push_back(k*5);
newvector.resize(newvector.size()+3);
std::copy_backward ( newvector.begin(), newvector.begin()+5, newvector.end() );
std::cout << "newvector contains:";
for (std::vector<int>::iterator ti=newvector.begin(); ti!=newvector.end(); ++ti)
std::cout << ' ' << *ti;
std::cout << '\n';
return 0;
}
Output:
newvector contains: 5 10 15 5 10 15 20 25
Complexity
The function's complexity increases linearly as it iterates from the initial element to the final one.
Data races
Some or all of the container entities are being retrieved.
Exceptions
The function will raise an exception if any of the container elements raises an exception.
