In this post, we show how to create a Java program to find Factorial of a given number. There is lot's of Factorial Programs out there on the internet using loops, recursive but here I use BigInteger.multiply() method to find Factorial of a given number.
Factorial of n is the product of all positive descending integers. Factorial of n is denoted by n!.
For example:
4! = 4*3*2*1 = 24
5! = 5*4*3*2*1 = 120
Java Factorial Program
In the below program, we are using a Scanner to get input from the console.
import java.math.BigInteger;
import java.util.Scanner;
public class FactorialExample {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a number: ");
int n = scanner.nextInt();
BigInteger fact = factorial(n);
System.out.printf("%d! is %d", n, fact);
scanner.close();
}
private static BigInteger factorial(int value) {
BigInteger result = BigInteger.ONE;
if (value != 0 && value != 1) {
for (int i = 2; i <= value; i++) {
result = result.multiply(BigInteger.valueOf(i));
}
}
return result;
}
}
Output:
Enter a number: 5
5! is 120
There are different techniques to write this program, check out this article.Related Java Programs
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