I want only answer for Q3 :)

BOOK: computer systems a programmer's perspective ebook (Bryant .O'Hallaron) 2nd edition

Q2) Write a program rw.c that will use system call read() and write() to read the input form the user and print it as output, one byte at a time.

a) Use strace command to check out the system call for read() and write().

strace e trace = read ./rw

strace e trace = write ./rw

b) Why using read() and write() system calls is not recommended?

Q3:

a) Modify the given program in question Q2 so that it uses ONLY buffered RIO functions.

b) What is the difference between the buffered RIO functions and standard I/O system calls?