UMBC CS 201, Fall 05
Recursion
Definition
recursion n. See recursion.
Recursion in Mathematics
A recursive definition is one which refers to itself as in these
definitions of the factorial and
fibonacci functions.
n! or fact(n) is defined as:
fact(0) = 1
fact(n) = n * fact(n1) , for n > 0
the nth fibonacci number or fib(n) is defined as:
fib(0) = 1
fib(1) = 1
fib(n) = fib(n1) + fib(n2) , for n > 1
Recursion in Programs
A recursive function is a function that calls itself.
 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));
}
}
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201 F'05

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Last Modified  Saturday, 05Nov2005 11:22:37 EST