import java.io.*;
class Factorial
{
    int fact(int n)
    {
        if(n<=1)
            return 1;
        else
            return n*fact(n-1);
    }
}
class RecursionFact
{
    public static void main(String args[]) throws IOException
    {
        int no;
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Enter a Number: ");
        no = Integer.parseInt(br.readLine());

        if(no<0)
        {
            System.out.println("Negative number is not acceptable.");
        }

        else
        {
            Factorial f=new Factorial();
            System.out.println("Factorial of "+no+" is: "+f.fact(no));
        }
    }
}

 OUTPUT:

Compile: javac RecursionFact.java

Run: java RecursionFact

Enter a Number:
5
Factorial of 5 is: 120

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