How does C++ count the number of a factorial 0?

This article mainly explains how C++ counts the number of multiplications of zeros. Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Next let the editor to take you to learn "C++ how to count a factorial 0" bar!

Here, the calculation formula is given first, and then the derivation process is given.

Let f (x) denote the number of zeros at the end of a positive integer x, then:

When 0

When = 5, f (n!) = k + f (k!), where k = n / 5 (rounded).

Calculation example

F (5!) = 1 + f (1!) = 1

F (10!) = 2 + f (2!) = 2

F (20!) = 4 + f (4!) = 4

F (100!) = 20 + f (20!) = 20 + 4 + f (4!) = 24

F (1000!) = 200 + 40 + f (40!) = 240 + 8 + f (8!) = 248 + 1 + f (1) = 249

# include using namespace std;int CountZero (int n) {if (nx5) {n = count 5; count = count + n;} return count;} int main () {int N; cin > > N; cout