Java Program for fining factorial of a number

Are you wondering how to seek help from subject matter experts and learn the Java language? Go with these Basic Java Programming Examples and try to code all of them on your own then check with the exact code provided by expert programmers.

Program for fining factorial of a number

In this article we will see different way to find out the factorial of a number .

Concept :

Factorial is mostly used in permutation and combination. It is  calculated as the product of the all positive number from 1 to n. for example if the number is N , then the factorial would be ( 1 x 2 x 3 x ….. x N) .

The factorial value of 0 is ‘1’.
There is no factorial value for negative number .

Example : 

number =5 
factorial = 1 x 2 x 3 x 4 x 5 =120

Now we will see 2 different ways to do it.

Method 1: By using for loop

By using for loop we can calculate the factorial of a number.

Approach :

  • Enter a number .
  • Take a variable and initialize 1 into it .
  • Take a for loop form 1 to that number and for each step multiply the value with that variable .
  • Print the value .

Program :

import java.util.Scanner;
class Main{  
 public static void main(String args[])
 {  
    int x,f=1, n ;
    // creating object .
    Scanner sc = new Scanner(System.in);
    // entering a number .
    System.out.println("Enter a number :");
    n = sc.nextInt(); 
    sc.close();
  //calculating factorial value .    
  for(x=1;x<=n;x++)
  {    
      f=f*x;    
  }    
  // printing factorial value 
  System.out.println("Factorial of "+n+" = "+f);    
 }  
}  
Output:

Enter a number :
5
Factorial of 5 = 120

Method 2: By using while loop

By using while loop we can calculate the factorial of a number.

Approach :

  • Enter a number .
  • Take a variable and initialize 1 into it .
  • Take a while loop form 1 to that number and for each step multiply the value with that variable .
  • Print the value .

Program:

import java.util.Scanner;
class Main
{  
 public static void main(String args[])
 {  
    int x=1,f=1, n ;
    // creating object .
    Scanner sc = new Scanner(System.in);
    // entering a number .
    System.out.println("Enter a number :");
    n = sc.nextInt();
    sc.close();
  //calculating factorial value .    
  while(x<=n)
        {
            f  = f * x;
            x++;
        }  
  // printing factorial value 
  System.out.println("Factorial of "+n+" = "+f);    
 }    
}  
Output:

Enter a number :
5
Factorial of 5 = 120

Get started with learning the programming language Java from beginner to experienced level by referring to our collection of Java Programs with Source Code and become a pro in the subject.

Related Java Decision Making and Loop Programs: