Question

Let’s say I have my data in a 4 by 3 vector<vector<int> > as:

1   2   3
4   5   6
7   8   9
10  11  12

and I want to delete every row containing the element 8 and end up like:

1   2   3
4   5   6
10  11  12

I have been trying to do:

for (vector<vector<int> >::iterator it = v.begin(); it != v.end(); it++) {
    if (find(it->begin(), it->end(), 8)) {
        // I will remove the row in here
    }
}

which gives me:

error: no matching function for call to 'find(std::vector<int>::iterator, std::vector<int>::iterator, int)'

I don’t have much experience with stl so I was wondering:

• what’s wrong with my find call?
• is it safe to remove an element from a vector while iterating over it?

Ofc any elegant solution to my problem is also welcomed..

Answer 1

what’s wrong with my find call?

You probably forgot to #include <algorithm>

is it safe to remove an element from a vector while iterating over it?

Look into the erase-remove idiom – erasing vector elements can be tricky.