Get index of object inserted into a vector

Question

How can I get the position where my object was actually inserted?

#include <vector>
using namespace std;

vector<SomeClass> list;
SomeClass object;
list.push_back(object);

list[...].method(); // I do not have the key

Unfortunately push_back does not return anything since its return type is void.

Answer 1

If v is your vector, the following will give you the position (that is, the index):

v.push_back(object);
size_t pos = v.size() - 1;

Or you can look at the size() before calling push_back(). Then you won't need to subtract one.

Answer 2

You can use the back() member to obtain a reference to the last element:

list.push_back(object);
list.back();

Or, since push_back() simply adds the object to the end, the index of the newly-inserted element is the vector size minus one:

list.push_back(object);
vector<my_class>::size_type object_pos = list.size() - 1;