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how to find factorial in java

how to find factorial in java

In this article, we will learn how to find the factorial of a number in java. The factorial of a number is the product of all the integers from 1 to that number.

Factorial of a non-negative integer, is multiplication of all integers smaller than or equal to n. For example factorial of 6 is 6*5*4*3*2*1 which is 720.

how to find factorial in java

We will implement 5 Different Ways to find the factorial number in java.

E.g:

  1. Java Program Using For Loop
  2. Using Command Line Arguments
  3. Using Function
  4. Using Recursion
  5. Using while loop

Example 1:

Java Program To Calculate Factorial using standard values with outputs

Standard values – consider the following code is universally applicable- with sample outputs.

<strong>Method 1:</strong> Java Program To Calculate Factorial using standard values with outputs

class Factoral
{
public static void main(String arg[])
{
int n=5,fact=1;

        for(int i=1;i<=n;i++)
      {

           fact=fact*i;
       }

         System.out.println("factoral="+fact);
}

}

Output:

factorial = 120

Example 2:

Java Program Using For Loop

Among all three loops, for loop is probably the most used loop. For loop are two types mainly:

  1. for each style of for loop
  2. normal for loop

<strong>Method 2:</strong> Java Program Using For Loop
class Factorial
{
	public static void main(String arg[])
	
	{
	
            long n,fact=1;
	
	    Scanner sc=new Scanner(System.in);
 
	    System.out.println("enter number");
	   
            n=sc.nextLong();
 
	    for(int i=1;i<=n;i++)
	    {
	
	    fact=fact*i;
 
 	    }
 
  	    System.out.println("fact="+fact);
 
	}
 
}

Output:

enter number
7 = 5040

Example 3:

Using Command Line Arguments

<strong>Method 3:</strong> Using Command Line Arguments 
import java.util.Scanner;
class Factorl
{
	public static void main(String args[])
	
	{
              long n,fact=1;	   
 
              n=Long.parseLong(args[0]);
 
	      for(int i=1;i<=n;i++)
	      {
	    	     fact=fact*i;
 	      }
 
  	      System.out.println("fact="+fact);
	}
}

Output:

Java Factorl 9
fact = 362880

Example 4:

Using Function

<strong>Method 4:</strong> Using Function 
import java.util.Scanner;
class Factorl
{
	public static void main(String args[])
	
	{
	
           long n,fact=0;
 
	   n=Long.parseLong(args[0]);		   
                  
           fact=factCal(n);
 
           System.out.println("fact="+fact);
 
	}
	
	static long factCal(long x)
	{
	    long fact=1;
	    for(int i=1;i<=x;i++)
	    {
	
	    	fact=fact*i;
 
 	    }
	    return fact;
	}
 
}

Output:

java Factorl 10 

fact = 3628800

Example 5:

Using Recursion

Recursion: A Recursion is a function call itself – you can check out more information about what is recursion in java here?

<strong>Method 5</strong> Using Recursion
class Factorl
{ 
	public static void main(String arg[])	
	{
	   long n;
             	
           Scanner sc=new Scanner(System.in);
 
	   System.out.println("enter number");
	   
           n=sc.nextLong();
 
	   long f=Factorl.fact(n);
 
	   System.out.println("factorial="+f);
	}
 
	static long fact(long n)
	 {
	     if(n<=0)
	      return 1;
	      
              return Factorl.fact(n-1)*n; 
	}
}

Output:

enter number

30

Factorl=8764578968847253504

Example 6:

Using while loop

<strong>Method </strong>6 Using while loop
import java.util.Scanner;
 
class Factrl
{
	public static void main(String arg[])
	
	{
	
            long n,fact=1;
	
	    Scanner sc=new Scanner(System.in);
 
	    System.out.println("enter number");
	   
            n=sc.nextLong();
int i=1;
	    while(i<=n)
	    {
	
	    fact=fact*i;
                     i++;
 	    }
 
  	    System.out.println("fact="+fact);
 
	}
}

Output:

enter number
10
fact=3628800

how to find factorial in java – how to find factorial in java – how to find factorial in java – how to find factorial in java – how to find factorial in java