Bloomberg Software Developer interview questions

The interview lasts about 50 minutes. I was asked some questions about c++ since I said to interviewer that i am more comfortable with c++. The questions were like, what is function overloading, how does compiler achieve overloading and virtual function. And, I was asked a question: given an array, all the elements in the array appear twince, only one element appears only once. Find that element. Eg, the array is 2 4 2 3 4 1 3 6 6, 1 should be the answer. I said this can be solved using map, I guess there should be some more efficient ways. Finally I was asked to implement a function about pointers and memory management. The idea is you should use char ** str as the argument since the pointer in argument will be pass-by-value. I didn't do well in the interview. I guess that is it. Anyway, a good experience.