Whats the difference between <stdio.h> and <iostream>?

Question

is there any problem if I use <stdio.h> ?

Answer 1

iostream is the c++ library for input and output
stdio.h is the c standard library for input and output
they are really different, but you can use stdio.h if you want.
by the way if you write c++ code is preferable to use iostream

Answer 2

one for c++ and other one for c