### Factorial of number in Java.

Factorial of number in Java. Factorial of number is product of a number and all number below it. Example:

**5! = 5 * 4 * 3 * 2 * 1 = 120.**

Factorial of 3

**3! = 3 * 2 * 1 = 120.**

**Note: The value of 0! is 1**

Below you can get Factorial of number till 20.

### Algorithm

Lets see algorithm for printing Factorial of a Number.

We will see 3 ways of finding Factorial of number,

- Recursive Implementation
- Iterative Implementation
- Using BigInteger for Large values.

**Check Recursive Implementation Program flow below.**

### Java Program to Print Factorial of a number using Recursion.

package javabypatel; import java.math.BigInteger; public class FindFactorialOfNumber { public static void main(String[] args) { System.out.println(factRecursive(5)); System.out.println(factIterative(5)); System.out.println(factorialForLargeNumbers(5)); } //Recursive Implementation private static int factRecursive(int num){ if(num < 0){ return -1; } if(num == 1 || num == 0){ return 1; } num = num * factRecursive(num-1); return num; } //Iterative Implementation private static int factIterative(int num){ if(num < 0){ return -1; } int fact = 1; for (int i = 1; i <= num; i++) { fact *= i; } return fact; } //Using BigInteger for Large values public static String factorialForLargeNumbers(int num) { if(num < 0){ return "-1"; } BigInteger fact = new BigInteger("1"); for (int i = 1; i <= num; i++) { fact = fact.multiply(new BigInteger(String.valueOf(i))); } return fact.toString(); } }

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**Enjoy !!!!**

**If you find any issue in post or face any error while implementing, Please comment.**

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