matrix multiplication 3x3 for loops???

So basically I have to tell the user to input data and i use a for loop:
for (i=0; i< 3; i++)
cin >> p[i][0],p[i][1], p[i][2];

now for the confusing part is, what do i put in the nested for loops to multiply them and output them so it looks something like

matrix p,r1: # # #
" ",r2: " "
" " " "

thanks

If you were mutiplying 3x3 matrices on paper by hand, how would you do it? When you know how you would do it by hand, then you know the algorithm and then you can can code the algorithm in c++.

You might like to read this
http://msdn.microsoft.com/en-gb/library/hh873134.aspx