This presentation is about recursion in c++ with examples.

1. Recursion in c++.
By
Abdulrehman.

2. Recursion:
 A programming technique in which a function calls
itself is known as recursion.
 A function that calls itself is called recursive function.

3. Example:(Factorial of a number using recursion):
#include<iostream.h>
#include<conio.h>
int factorial(int); // declaring function prototype...
int main(){
clrscr();
int n;
cout<<”Factorial of which number..”<<endl;
cin>>n;

4. cout<<factorial(n);
return 0;
}
//******Factorial function********
int factorial(int n){
if(n==0)
return 1;
else
return n * factorial(n-1);
}

5. FACTORIAL OF NUMBER 5.
1) 5 * factorial(4)-------->5.
2) 4 * factorial(3)-------->4.
3) 3 * factorial(2)-------->3.
4) 2 * factorial(1)-------->2.
5) 1 * factorial(0)-------->1.
6) factorial(0)=1.
hence factorial=5*4*3*2*1*1=120.

6. Fibonacci series program using recursion.
0 , 1 , 1 , 2 , 3 , 5 , 8 , 13 , ..........<---Fibanacci series.
#include"iostream.h"
#include"conio.h"
int fibonacci(int); // prototype of fibanacci function..
int main(){
clrscr();
int n;
cout<<"Enter the length of series.."<<endl;
cin>>n;

7. cout<<"The fibonacci series is given below.."<<endl;
for(int i=0;i<n;i++){
cout<<fibonacci(i)<<" ";
}
return 0;
}
int fibonacci(int n){ // 0,1,1,2,3,5....
if ((n==0)||(n==1))
return n;
else
return (fibonacci(n-1)+fibonacci(n-2));}