This assignment deals with the combination of dynamic memory allocation and structures to create a common data structure known as a doubly-linked list, which is shown in Figure 1.

Figure 1: Doubly-linked list in which each node contains three fields--pointers to the previous and next nodes in the list, and a single integer as data.

The boxes containing 'X' at the beginning and end of the list show that the first and last nodes have NULL pointers for their previous and next pointers, respectively. The pointers to the first and last nodes, which allow the list to be traversed in either direction, are not shown. The list you will implement is a sorted doubly-linked list in which the data stored in each node is a string, and the nodes are sorted in alphabetical order. You will complete four functions, which allow you to add or delete a node, find a node containing a given string, or print the entire contents of the list.

2. Deliverables This assignment uses multiple files, each of which is provided on the course web page:

• prog10_main.c: Main program. Do not change the contents of this file.
• DLList.h: Header file that contains structure definitions and function prototypes to be used in this assignment. Do not change the contents of this file.
• DLList.c: Definitions for the functions described in DLList.h. You should only complete the functions in this file-do not change any of the #include statements, structure definitions, or function prototypes (i.e., function return types and arguments). To complete this assignment, you will complete each of the functions in DLList.c. If each function is properly written, the entire program will work correctly. All three files must be included when compiling your code-see Section 6 for a description of how to add multiple files to a Visual Studio project.