Let’s learn factorial program in java.

## Factorial program in java

Factorial is nothing but the product of all numbers less than or equal to given number. Denoted as n! For example,

6! = 6 * 5 * 4 * 3 * 2 * 1 = 720 (6! means 6 factorial)

4! = 4 * 3 * 2 * 1 = 24 (4! means 4 factorial)

Let’s see java program using for loop,

public class FactorialDemo { public static void main(String[] args) { int number = 6, factorial = 1; for(int a = 1; a <= number; a++) { factorial = factorial * a; } System.out.println("Factorial of " + number + " is : " + factorial); } }

**Output:**

Factorial of 6 is : 720

**Using recursion**

public class FactorialRecursion { public static void main(String[] args) { int factorial = 1; int number = 6; factorial =factorialFunction(number); System.out.println("Factorial of " + number + " is : " + factorial); } static int factorialFunction(int num) { if(num == 0) { return 1; } else { return(num *factorialFunction(num - 1)); } } }

**Output:**

Factorial of 6 is : 720

**Using while loop**

Also read – sum and average of values in an array in java

import java.util.Scanner; public class FactorialWhile { public static void main(String[] args) { int number, factorial = 1; Scanner sc = new Scanner(System.in); System.out.println("Please enter a number : "); number = sc.nextInt(); int a = 1; while(a <= number) { factorial = factorial * a; a++; } System.out.println("Factorial of " + number + " is : " + factorial); sc.close(); } }

**Output:**

Please enter a number : 5

Factorial of 6 is : 120

**Using do while loop**

import java.util.Scanner; public class FactorialDoWhile { public static void main(String[] args) { int number, factorial = 1; Scanner sc = new Scanner(System.in); System.out.println("Please enter a number : "); number = sc.nextInt(); int a = 1; do { factorial = factorial * a; a++; } while(a <= number); System.out.println("Factorial of " + number + " is : " + factorial); sc.close(); } }

**Output:**

Please enter a number : 7

Factorial of 7 is : 5040