random

I am trying to write a program that reads from a file(easy) which contains names of restaurants, and their category.
Now what I want to program to do is have a menu such as:

Pick an option from the list below:
[r]random restaurant
[s]search restaurants by cetegory
[a]add a restaurant to the database
[d]delete a restaurant from the database
[x]quit the program

All I need help with here is the randomization. And for such a program should I use a dynamic character array, or a linked list?