Trying to do this in C++

Question 5: Write a program that reads a person's name in the following format: first name, then middle name or initial, and then last name. The program then outputs the name in the following format: Last_Name, First Name Middle_Initial. For example, the input Mary Average User should produce the output: User, Mary A The input Mary A. User should also produce the output: User, Mary A. Note that your program should work the same and place a period after the middle initial even if the input did not contain a period. Hint: You may want to use three string variables rather than one large string variable for the input. You may find it easier to not use getline