Recursion

Definition

recursion n. See recursion.

Recursion in Mathematics

n! or fact(n) is defined as:

     fact(0) = 1  
     fact(n) = n * fact(n-1) , for  n > 0

the nth fibonacci number or fib(n) is defined as:

     fib(0) = 1
     fib(1) = 1
     fib(n) = fib(n-1) + fib(n-2) , for  n > 1 

Recursion in Programs

• Each time the function calls itself, it gets a new set of parameters and local variables.
• The parameters and local variables from a previous call to the recursive function will still be preserved until the function returns from the previous call.

The Factorial Function in C

int Factorial (int n)
{
   if(n == 0)
   {
      return (1);
   }
   else
   {
      return (n * Factorial(n - 1));
   }
}