[STL]back_inserter 与back_insert_iterator
back_inserter一个成员函数，返回值是back_insert_iterator, 本质上是push_back进行操作的, 返回值back_insert_iterator, 并实现其自增.
std::vector<int> firstvector, secondvector;
for (int i=1; i<=5; i++)
{
firstvector.push_back(i);
secondvector.push_back(i*10);
}
// 在firstvector向量后面加入secondvector的值.
std::copy(secondvector.begin(), secondvector.end(), std::back_inserter(firstvector));
std::vector<int>::iterator it;
for ( it = firstvector.begin(); it!= firstvector.end(); ++it )
std::cout << *it << " ";
std::cout << std::endl;
下面是一个back_insert_iterator的例子
std::vector<int> vec;
for (int i = 0 ; i < 3; ++i)
vec.push_back(i);
std::vector <int>::iterator vIter;
std::cout << "The initial vector vec is: ( ";
for (vIter = vec.begin(); vIter != vec.end(); vIter++)
std::cout << *vIter << " ";
std::cout << ")." << std::endl;
// Insertions can be done with template function
std::back_insert_iterator<std::vector<int> > backiter(vec);
*backiter = 30;
backiter++;
*backiter = 40;
// Alternatively, insertions can be done with the
// back_insert_iterator member function
std::back_inserter(vec) = 500;
std::back_inserter(vec) = 600;
std::cout << "After the insertions, the vector vec is: ( ";
for (vIter = vec.begin(); vIter != vec.end(); vIter++)
std::cout << *vIter << " ";
std::cout << ")." << std::endl;
