Java Program to find Factorial Number

Last Updated: 14 March, 2023

On this tutorial page we are going to learn how to write a Java program to find Factorial Number.

A factorial number is the product of all positive integers from 1 to a given number. For example, the factorial of 5 is 5 x 4 x 3 x 2 x 1 = 120. The symbol used to represent the factorial operation is an exclamation mark (!). So, 5! is read as "five factorial" and is equal to 120.

Program 1: Find the factorial of a number in Java using while loop

  
  // Find factorial of a number using while loop
  public class FactorialNumber {
    public static void main(String[] args) {
      
      int number = 5;
      int factorial = 1;
      int i = 1;
      
      while (i <= number) {
        factorial = factorial * i;
        i++;
      }
      
      System.out.printf("Factorial of %d = %d", number, factorial);
    }
  }

Output

Factorial of 5 = 120

Program 2: Find the factorial of a number in Java using for loop

  
  // Find factorial of a number using for loop
  public class FactorialNumber2 {
    public static void main(String[] args) {
      
      int number = 5;
      int factorial = 1;
      
      for (int i = 1; i <= number; ++i) {
        factorial = factorial * i;
      }
      
      System.out.printf("Factorial of %d = %d", number, factorial);
    }
  }

Output

Factorial of 5 = 120

Program 3: Find the factorial of a number in Java using Scanner class (user input)

  
  // Find factorial of a number using recursion
  public class FactorialNumber3 {
    public static void main(String[] args) {
      
      Scanner scanner = new Scanner(System.in);
      System.out.println("Enter the number: ");
      int number = scanner.nextInt();
      scanner.close();
      
      int factorial = fact(number);
      System.out.printf("Factorial of %d = %d", number, factorial);
    }
    
    static int fact(int num) {
      if (num == 1) {
        return 1;
      }
      // Recursion: fact() function calling itself
      return fact(num - 1) * num;
    }
  }

Output

Enter the number: 5
Factorial of 5 = 120