This C program implements functions for a singly linked list including inserting and deleting nodes from different positions as well as displaying the list. The main function uses a switch case to allow the user to choose an operation on the list such as inserting a new node at the beginning, end, or a specified position. Other operations include deleting nodes from the beginning, end, or a specified position. The length of the list is tracked and positions are validated. Pointers are used to traverse the list and add/remove nodes as needed.