i want that the number of address book item is not known in advance, i am thinking to use linked list is it the right choice??

"the user can enter new person data, or print the data for a given name, the asking data need not be a name but also an address on a telephone number, the program prints the whole information about a person, print the content of the book in alphabetical order. Store some data in a file; retrieve it and safe it after modification

Program should write a file to the disk and retrieve the file from it. Program should be called with arguments.

i will use malloc but i don't know when and how?

somebody did similar task or have an idea can help me plz