C ++如何初始化4个空集的向量

Question

For a vector of vectors, I would do this:

vector<vector<int> > A(10, vector<int>(10));

So I tried this for a vector of sets:

vector < set <object*> > mySet(4, set<object*>);

..but it won't compile. Any advice?

Answer 1

You are almost right: even though you do not need to specify the size, you still need an empty pair of parentheses:

vector<set<object*>> vsi(4, set<object*>());
//                                      ^^

Moreover, since you are using the default constructor, you could simply omit the second argument, like this:

vector<set<object*>> vsi(4);