C Programming

std::vector<int> cntr;
// ... put ints in the container
std::vector<int>::iterator iter;
for (iter = cntr.begin(); iter != cntr.end(); iter++)	{
    // --- access *iter
    cntr.push_back(123);  // add an object to the container
    // --- iter is no longer valid!
}

Example 1: An iterator gone bad.