Addressbook using double

代码说明：

Addressbook using double-linked list. This example shows the use of a double-linked list by implementing an addressbook for the console. It has features like inserting, searching(linear), sorting(bubble sort), deleting and load/save to a file. I wrote this during my study of Applied Computer Science so it s intended mainly for students who want to know about some advanced programming techniques in C. The Code was compiled with MSVC++ 6.0 but it should compile with any ANSI-compliant compiler.