(C++) std::copy

std::copy is an STL algorithm to copy container elements.

std::copy assumes that the memory data is copied to is valid. For example, if you copy a std::vector of size 10 to another std::vector, the latter must have a size of 10 at least. But if the size is unknown, use an inserter like std::back_inserter.

Related algorithms are:

• std::copy_backward: copy values to the back of a container
• std::copy_if: for performing a conditional copy
• std::transform: for copy and modify

Prefer algorithm calls over hand-written loops [1, 2].

Example: Append

#include <algorithm>

template <class Container>
void append(Container& to, const Container& from)
{
  std::copy(std::begin(from), std::end(from), std::back_inserter(to));
}

Example: CoutVector

#include <iostream>
#include <iterator>
#include <ostream>
#include <vector>

template <class T>
void cout_vector(const std::vector<T>& v)
{
  std::copy(std::begin(v), std::end(v), std::ostream_iterator<T>(std::cout,"\n"));
}

External links

• SGI's page about std::copy
• cplusplus.com page about std::copy

References

• [1] Bjarne Stroustrup. The C++ Programming Language (3rd edition). ISBN: 0-201-88954-4. Chapter 18.12.1: 'Prefer algorithms to loops.
• [2] Scott Meyers. Effective STL. ISBN: 0-201-74962-9. Item 43: 'Prefer algorithm calls over hand-written loops'