Finding Factorial Of A Number In Java

This illustrates finding factorial of a number algorithm in Java. Here i didn't use any methods for finding factorial, it is just the logic.

 import java.util.*;
class FindFactorial
{
    public static void main(String args[])
    {
    int n;
    System.out.println("Enter the number");
    Scanner s=new Scanner(System.in);
    n=s.nextInt();

    // If user enters 0 then 0!=1
    long f=1;

        for(int i=n;i>=1;i--)
        {
        f*=i;
        }
    System.out.println("Factorial of "+n+" is "+f);
    }
}
 

Sample Output

 Enter the number
7
Factorial of 7 is 5040
 

Analysis

f=1: When user gives 0 as input, then 0!=1
The Loop: Loop is looped till n decreases to 1
f*=i: It is equal to f=f*i;. This is a simple factorial logic.

For people, who don't know what is factorial of a number, i could explain them with the help of examples for a better understand.

 5!=5*4*3*2*1=120;
 6!=6*5*4*3*2*1=6*(5!)=720;

Also see Finding Divisors of a number in Java

In this way, we can simply find factorial of a number without using any factorial function not only in Java but in any language.

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