Use the vector::erase function to erase an element, or range of elements from a vector. It returns an iterator pointing to the element after the last one erased:
v.erase(v.begin() + pos); v.erase(v.begin() + start, v.begin() + end);
For example, this program populates a vector with the numbers 0 to 9 and then erases 8, before erasing 3 to 5:
#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
int main()
{
typedef std::vector<int> intvec;
intvec v(10);
std::iota(v.begin(), v.end(), 0);
std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " "));
std::cout << "\n";
std::cout << "erase 8:\n";
intvec::const_iterator it = v.erase(v.begin() + 8);
std::cout << "next element is " << *it << "\n";
std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " "));
std::cout << "\n";
std::cout << "erase 3 to 5:\n";
it = v.erase(v.begin() + 3, v.begin() + 6);
std::cout << "next element is " << *it << "\n";
std::copy(v.begin(), v.end(), std::ostream_iterator<int>(std::cout, " "));
std::cout << "\n";
}
You can make a generic function to erase from a container by index by using std::advance to move to the first (and optionally last) element to remove and then calling the container’s own erase method:
template <class Container>
typename Container::iterator erase(Container& cont, size_t pos, size_t len = 1)
{
typename Container::iterator it1 = cont.begin();
std::advance(it1, pos);
typename Container::iterator it2 = it1;
std::advance(it2, len);
return cont.erase(it1, it2);
}
Use it like this:
erase(vec, 8); // erase 8 erase(vec, 3, 3); // erase 3 to 5
Note that this will be O(n) for lists because their iterators are not RandomAccessIterators.