Can someone help me out this program ?

I want write a program to print out first name, last name, middle name and initial name of 3 letter of last, first, and middle ?

Rose Li Lee

R L L

I just know the basic c ++

int main()

string lastname, firstname, middlename;

cin >> lastname >> firstname >> middlename;

that easy, but what can I do if I want come out firstname, lastname, middlename and initial name?

Thank