factorial number in java

1 int num1 = 6; 
2 int num2 = 1;
3    for(int a = 1; a<=num1; a++) {
4        num2 = num2 * a;
5    }
6        System.out.println(num2);

1// Factorial program using recursion
2public class FactorialRecursion
3{
4   public static void main(String[] args)
5   {
6      int factorial = 1;
7      int number = 6;
8      factorial = factorialFunction(number);
9      System.out.println("Factorial of " + number + " is : " + factorial);
10   }
11   static int factorialFunction(int num)
12   {
13      if(num == 0)
14      {
15         return 1;
16      }
17      else
18      {
19         return(num * factorialFunction(num - 1));
20      }
21   }
22}

1public class FactorialDemo
2{
3   public static void main(String[] args)
4   {
5      int number = 6, factorial = 1;
6      for(int a = 1; a <= number; a++)
7      {
8         factorial = factorial * a;
9      }
10      System.out.println("Factorial of " + number + " is : " + factorial);
11   }
12}

1double factorial = 1;
2double number=30;
3
4while ( numero!=0) {
5  factorial=factorial*number;
6  number--;
7}