Trailing_zeros_in_factorial

 

Method 1:

public class j05_trailing_zeros_in_factorial {

    static int countTrailingZeros(int n){

        int ans = 0;

        for (int i = 5; i < n; i=i*5) {

            ans = ans+n/i;

        }

        return ans;

    }

    public static void main(String[] args) {

        int number = 251;

        System.out.println(countTrailingZeros(number));

    }

}

Method 2:

public class j05_trailing_zeros_in_factorial {

    static int countTrailingZeros(int n){

        int ans = 0;

        for (int i = 5; i < n; i=i*5) {

            ans = ans+n/i;

        }

        return ans;

    }

    static int fact(int n){

        int fact = 1;

        for (int i = 2; i <= n; i++) {

            fact = fact*i;

        }

        return fact;

    }

    static int countTrailingZeros(int n){

        int ans=0;

        long fact = fact(n);

        while(fact%10==0){

            ans++;

            fact=fact/10;

        }

        return ans;

    }

    public static void main(String[] args) {

        int number = 251;

        System.out.println(countTrailingZeros(number));

    }

}