Question

1. Implement a method factorial(int n), that takes a number (int) and returns its factorial. Factorial of an integer is the product of all positive integers less than or equal to it. Method needs to be implemented using recursion.

Answer 1

import java.io.*;

import java.util.*;

public class Main

{

public static int factorial(int n){

if (n == 0)

return 1;

else

return(n * factorial(n-1)); //recursively calling factorial function

}

public static void fibbonaci(int n)

{

if(n>0)

{

c=a+b; //next term in series

a=b;

b=c;

System.out.print(" "+c);

fibbonaci(n-1); //recursively calling fibbonaci function

}

}

static int a=0,b=1,c;

public static void main(String[] args) {

int list_num,fact;

List<Integer> num=Arrays.asList(1,3,5,7,9); //arraylist with 1,3,5,7,9

for(Integer i:num) //for-each loop

{

a=0;

b=1;

list_num=i.intValue();

System.out.println("Fibbonaci series for "+list_num);

System.out.print(a+" "+b);

fibbonaci(list_num-2); //calling fibbonaci for values in list

fact=factorial(list_num); //calling factorial for values in list

System.out.println();

System.out.println("Factorial for "+list_num+" is "+fact);

System.out.println();

}

}

}