Pass a vector starting from index i by reference

I am writing a function in C++

int maxsubarray(vector<int>&nums) 

say I have a vector

v={1,2,3,4,5}

I want to pass

{3,4,5} 

to the function,i.e. pass the vector starting from index 2. In C I know I can call maxsubarray(v+2) but in C++ it doesn't work. I can modify the function by adding start index parameter to make it work of course. Just want to know can I do it without modifying my original function? THX