Ericsson Graduate Engineer Trainee interview questions

1. I was asked a simple code to find the sum of digits in a number. 2. A puzzle for how would you cut a cake in 8 pieces in 3 slices. 3. How would you swap two numbers without using a temporary variable. For this question i used bit masking technique ..the interviewer was very impressed. 4. He also asked about the projects i had made and if i had the knowledge of DBMS.