Factorial Trailing Zeros

Factorial Trailing Zeros.cpp

#include <bits/stdc++.h>

#define MEM(a,b) memset((a),(b),sizeof(a))
#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIn(a,b) ((a)<(b)?(a):(b))
#define MIn4(a,b,c,d) MIn(MIn(MIn(a,b),c),d)
#define In freopen("In.txt", "r", stdin);
#define Out freopen("out.txt", "w", stdout);

#define i64 long long
#define u64 long long unsigned

#define sz 1000000

using namespace std;

// How trailing zeros being calculated?
//Input: 100
// So divide it using 5 repeatedly until 0
// and sum all the results
// 100/5 = 20
// 20/5 = 4
// 4/5 = 0
// so the result: 20+4 = 24
// Means there are 24 zeros from the last of 100!

int trailingZeros(int n)
{
    //Calculating Trailing Zeros
    //Recursion
    if(n==0)
        return 0;
    return n/5 + trailingZeros(n/5);
}

int main()
{
    int n;
    while(cin >> n)
        cout << trailingZeros(n) << endl;
    return 0;
}