【Java】两种方法计算出阶乘尾部连续0的个数

import java.util.Scanner;
import java.math.BigDecimal; 
import java.text.DecimalFormat; 
public class jc{
	public static void main(String args[]){
		Scanner reader = new Scanner(System.in);
		DecimalFormat a = new DecimalFormat("#");
		int num;
		num = reader.nextInt();
		double sum=1;
		for(int i=2;i<=num;i++){
			sum*=i;
		}
		//System.out.println(sum);
		//System.out.println(cal_the_number_of_zero(sum+""));
		System.out.println(a.format(sum));
		System.out.println(cal_the_number_of_zero(a.format(sum)));
	}
	public static int cal_the_number_of_zero(String str){
		int num=0;
		for(int i=0;i<str.length();i++){
					
			if(str.charAt(i)=='0'){
				num++;	
			}
			else{num=0;}	
		}
		return num; 
	}
}

import java.util.Scanner;

public class Main{ 
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int ret =0; 
        for(int i=n;i>=5;i--){
            int tmp =i;
            while(tmp%5==0){
                ret++;
                tmp=tmp/5;
            }
        }
        System.out.println(ret);
    }
}