There have been a few questions regarding this issue before; my understanding is that calling std::vector::erase
will only invalidate iterators which are at a position after the erased element. However, after erasing an element, is the iterator at that position still valid (provided, of course, that it doesn't point to end()
after the erase)?
My understanding of how a vector would be implemented seems to suggest that the iterator is definitely usable, but I'm not entirely sure if it could lead to undefined behavior.
As an example of what I'm talking about, the following code removes all odd integers from a vector. Does this code cause undefined behavior?
typedef std::vector<int> vectype;
vectype vec;
for (int i = 0; i < 100; ++i) vec.push_back(i);
vectype::iterator it = vec.begin();
while (it != vec.end()) {
if (*it % 2 == 1) vec.erase(it);
else ++it;
}
The code runs fine on my machine, but that doesn't convince me that it's valid.