Amazon Software Developer interview questions

phone interview for full time position. I posted my CV last year, maybe almost 6 month ago. And I do not know why they contact me at this time. I am not well prepare, just do it as some exercise. I do not get any reply and this is really wired.

So I had the first phone interview with Amazon. It is exactly 45 minutes and pretty technical. I had to write code in C++ or Java online in collabedit.com. He started by asking me to design a restaurant program, that is a program to simulate restaurant interactions, using object oriented design. This we kind of just talked through together, pretty easy. Then I was asked what the differences are between a linked list and an array, which if you can't answer you probably shouldn't be applying here. Then two pretty simple but tricky coding question: 1) Write a function that receives 2 parameters, a and b, and return a^b. 2) Write the above function recursively.