What is C++ auto_ptr. Simple search in google returns the answer. Difference between STL Vector and List - google again (dynamic memory allocation and so on). Difference between C++ struct and class - mainly that all members of a struct are public by definition. Also struct can not be used instead of typedef and class is a type. Implement atoi(const char* s) - I suggested something like { int count = 0; while (*s) { count = 10*count + (*s-0x30); s++; } } You are given an array which contains pairs of number and one number without a pair. Find the pair. For example, {1,4,1,6,8,4,6}. The number without a pair is 8. The expected answer is XOR between all numbers. What is GOF - Gang of four 4 authors of "Design Patterns: .. " Erich Gamma, Richard Helm or Gang of Four. Explain overloading and overriding in C++. Does Python support overloading? And so on. This was phone interview and I guess I could answer correctly all the questions if I search google every time. I decided that this is pointless in my case. I failed to answer most of the questions related to C++.