Factorial inward Java using Recursion together with Loop

Problem : Write a programme to calculate factorial of a given reveal inwards Java, using both recursion too iteration.

Solution : If yous come upward from Maths background so yous know that factorial of a reveal is number*(factorial of reveal -1). You volition role this formula to calculate factorial inwards this Java tutorial. Since factorial is a naturally recursive operation, it brand feel to role recursion to solve this employment only its non ever the best way. Iteration provides a to a greater extent than robust way, only don't worry yous volition larn how to calculate factorial amongst too without recursion inwards Java. By the way, factorial of numbers grows rattling apace too fifty-fifty the largest integral information type inwards Java, long is non able to concord factorial of anything or higher upward 50. In such cases yous tin role BigInteger, which has theoretically no throttle too tin live on used to correspond rattling large integral numbers.

Solution 1 : Factorial using recursion

In lodge to practise a recursive solution yous ask a base of operations illustration where programme terminates too inwards this employment base of operations illustration is factorial of 1, which is 1. So if given reveal is greater than 1, nosotros kicking the bucket on applying factorial formula too recursive telephone squall upward this method amongst n - 1 equally shown below :

 public static long factorial(int number){                 //base illustration - factorial of 0 or 1 is 1         if(number <=1){             return 1;         }                 return number*factorial(number - 1);     }

Once input kicking the bucket 1 the method stopped recursive telephone squall upward too render 1. From in that place onward stack started to gyre downward too in conclusion factorial of reveal is calculated.

Solution 2 : Factorial without Recursion

As I said instead of using recursion too calling factorial method i time again yous tin equally good role for loop to calculate factorial because !n = n*(n-1)*(n-2).....*1 , which tin easily live on implemented using loop equally shown below :

public static long factorial(long input){         long factorial = 1L;         for(long i= input; i > 0; i--){             factorial = factorial * i;         }                  return factorial;     }

You tin come across that nosotros outset amongst the reveal too multiply it amongst the factorial which is initialized amongst 1 so nosotros trim back the reveal yesteryear 1 until reveal becomes 1, which is naught but n*(n-1)*(n-2).....*1.

Write a programme to calculate factorial of a given reveal inwards Java Factorial inwards Java using Recursion too Loop

Java Program to calculate Factorial amongst too without Recursion

Here is our consummate solution of this problem. You tin come across that I receive got created two factorial() method, i convey int too render long e.g. long factorial(int number), field other convey a long too render a long factorial i.e. long factorial(long number). Since their parameter type is dissimilar they are 2 dissimilar method equally good known equally overloaded methods. First method uses recursion to calculate factorial field instant method uses iteration to calculate factorial.

import java.math.BigInteger; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar;  /**  * Java Program to calculate factorial using iteration too recursion  *   * @author WINDOWS 8  *  */ public class FactorialTest {      public static void main(String args[]) {                 System.out.println("factorial of 1 using recursion : " + factorial(1));         System.out.println("factorial of 1 using iteration : " + factorial(1L));                  System.out.println("factorial of v using recursion : " + factorial(5));         System.out.println("factorial of v using loop : "   + factorial(5L));                         System.out.println("factorial of vii using recursive algorithm : " + factorial(7));         System.out.println("factorial of vii using iterative algorithm : " + factorial(7L));               }         /**      * Java method to calculate factorial of given integer using recursion.      * @param reveal      * @return factorial of reveal      */     public static long factorial(int number){                  //base illustration - factorial of 0 or 1 is 1         if(number <=1){             return 1;         }                  return number*factorial(number - 1);     }          /**      * Java method to calculate factorial of given reveal using iteration      * @param input      * @return factorial of input      */     public static long factorial(long input){         long factorial = 1L;         for(long i= input; i > 0; i--){             factorial = factorial * i;         }                  return factorial;     }      }  Output : factorial of 1 using recursion : 1 factorial of 1 using iteration : 1 factorial of 5 using recursion : 120 factorial of 5 using loop : 120 factorial of 7 using recursive algorithm : 5040 factorial of 7 using iterative algorithm : 5040

That's all nigh how to calculate factorial of a reveal inwards Java using both recursion too iteration. This employment is oft used to learn programming, especially recursion inwards schoolhouse too colleges too its proficient i equally well. Just recollect that fifty-fifty though recursive solution are pocket-sized too clear they are prone to throw StackOverFlowException, thence non suitable for production code. Iteration or role of for loop results inwards to a greater extent than robust solution.

If yous are learning programming so yous tin equally good effort next employment to amend your logic too coding science :

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