Java Factorial Program

 

Program to calculate Factorial of given number.

/**
 * This program is used to calculate Factorial of given number.
 * @author W3schools360
 */
public class Factorial {
      /**
       * This method is used to calculate Factorial of given no.
       * @param num
       */

      static void factorialNumber(int num){
            int fact = 1;
            //Factorial of 0 and 1 is 1.
            if(num == 0 || num == 1){
              System.out.println("factorial of " + num + " is 1.");
            }

            //for calculating factorial, number should be non negative.
            if(num > 0){
              //calculate factorial.
              for(int i = 2; i <= num; i++){
                  fact = fact*i;
              }
              System.out.println("factorial of " + num + " is " +fact);
            }else{
              System.out.println("no. should be non negative.");
            }          
      }     

      public static void main(String args[]){
            //method call
            factorialNumber(5);
      }
}

Output:

factorial of 5 is 120