Sum of First N Natural Numbers & Factorial of A Number & The Fibonacci Sequence Till Nth Term Using Recursion in JAVA

 

import java.util.*;

public class Recursion {

// Q1. Print the sum of first n natural numbers.

    public static void sumOfNumbers(int n, int sum) {

        if (n == 0) {

            System.out.println("The Toal Sum is : "+sum);

            return;

        }

        sum = sum + n;

        sumOfNumbers(n - 1, sum);

    }

    // Q2. Print factorial of a number n.

    public static void factorial(int n, int fact) {

        if (n == 0) {

            System.out.println("The Factorial is : "+fact);

            return;

        }

        fact = fact * n;

        factorial(n - 1, fact);

    }

    // Q3. Print the fibonacci sequence till nth term.

    public static int fibonacci(int n) {

        if (n == 0) {

            return 0;

        }

        if (n == 1) {

            return 1;

        }

        int fib1 = fibonacci(n-1);

        int fib2 = fibonacci(n-2);

        int fib;

        return fib = fib1 + fib2;

    }

    public static void main(String[] args) {

        int n = 7;

         sumOfNumbers(n, 0);

       

         factorial(n, 1);

        System.out.println("The Fibonacci Sequence is ....");

        for(int i = 0; i<=n;i++){

        System.out.print(fibonacci(i)+" ");

        }

        System.out.println();

        System.out.println("The "+n+"th trem of Fibonacci Sequence is : "+fibonacci(n));

    }

}