Here is a Java program to find factorial of a number using recursion. We have to write a recursive function in Java to calculate factorial of a number. he factorial of a integer N, denoted by N! is the product of all positive integers less than or equal to n.

N! = 1 x 2 x 3 x 4....x (N-2) x (N-1) x N

We can use recursion to calculate factorial of a number because factorial calculation obeys recursive sub-structure property.

Let getfactorial(N) is a function to calculate and return value of N!. To find factorial(N) we can first calculate factorial(N-1) then multiply it with N.

getfactorial(N) = getfactorial(N-1) x N N! = (N-1)! x N N! = 1 x 2 x 3 x 4....x (N-2) x (N-1) x N

## Java program to find factorial of a number using recursion

package com.tcc.java.programs; import java.util.*; public class FactorialRecursion { public static void main(String args[]) { int num, factorial = 1, i; Scanner in = new Scanner(System.in); System.out.println("Enter an Integer"); num = in.nextInt(); factorial = getfactorial(num); System.out.println("!" + num + " = " + factorial); } public static int getfactorial(int num) { if (num <= 1) return 1; return num * getfactorial(num-1); } }Output

Enter an Integer 6 !6 = 720

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