Problem A linked list write a program that uses a linked list. Your program should wait for input from the keyboard. Entering from the keyboard an 'a' will just add the following number (read as next from the keyboard) to the end of the list, while a 'b' inserts at the beginning of the list. The character 'r' will remove the first element from the list, a 'p' will print the list while a 'q' will free the memory used by the list and quit the execution of the program. Use a switch-case statement to decide which action to take. You can assume that the input will be valid regarding the structure. To pass the testcases your output has to be identical with the provided ones. Testcase 3.1: input Testcase 3.1: output b 2 3 2 4 24 a 4 r Problem Multiple sources Modify your solution for Problem 3.1 such that you separate your source code into three files: struct declaration and function declarations in linked_list.h, function definitions in linked_list.c, and your main function in use_linked_list.c. Use exactly the provided names for your files. You can assume that the input will be valid. To pass the testcases your output has to be identical with the provided ones. Testcase 3.4: input Testcase 3.4: output 3 2 4 24 b 2 b 3 a 4 r