Removing item from vector while iterating?

Question

I have a vector that holds items that are either active or inactive. I want the size of this vector to stay small for performance issues, so I want items that have been mark

Answer 1

If someone need working on indexes

vector vector;
for(int i=0;i<10;++i)vector.push_back(i);

int size = vector.size();
for (int i = 0; i < size; ++i)
{
    assert(i > -1 && i < (int)vector.size());
    if(vector[i] % 3 == 0)
    {
        printf("Removing %d, %d\n",vector[i],i);
        vector.erase(vector.begin() + i);
    }

    if (size != (int)vector.size())
    {
        --i;
        size = vector.size();
        printf("Go back %d\n",size);
    }
}