Armstrong Number could anyone break this down elaborately?

Question

r = n%10;
c = r*r*r;
sum = sum + c;
n= n/10;

Answer 1

You did not initialize your variables...
Assuming that r, n, c, and Sum are integers...

r was assign to the value of the remainder of the division of n to 10.

c was assigned to the value of r to the power of 3

sum is assign the the initial sum value plus the value of c

Lastly, n is assign to the value of initial value of n that is divided by 10