Recursion

Recursion

• Function  repeatedly  call itself  is called recursion.
• Recursion is most important concept of object oriented programming.
• We can reduce the size of program using recursion
• Recursion solve some problem easily

Examples:

• Tower of Hanoi
• Fibonacci Series
• Factorial 

Let"s  take the code for Fibonacci series

CODE:

#include <iostream>

using namespace std;

int main()

{

    int a= 0, b = 1, nextTerm = 0, n;  //a  and  b are terms 

    cout << "Enter a positive number: ";

    cin >> n;

    // displays the first two terms 0 and 1

    cout << "Fibonacci Series: " << a << ", " << b << ", ";

    nextTerm = a + b;

    while(nextTerm <= n)

    {

        cout << nextTerm << ", ";

        a = b;

        a = nextTerm;

        nextTerm = a + b;

    }

    return 0;

}

OUTPUT:

Let"s  take the code for Factorial

CODE:

#include<iostream>

using namespace std;

int factorial(int n);

int main()

{

    int n;

    cout << "W.A.P. to find factorial of given number using recursion.\n\n\n";

    cout << "Enter a positive integer: ";

    cin >> n;

    cout << "Factorial of " << n << " = " << factorial(n);

    return 0;

}

int factorial(int n)

{

    if(n > 1)

        return n * factorial(n - 1);

    else

        return 1;

}

OUTPUT: