Question

does anybody know of a good source of really simple lessons about recursion? i'm trying to wrap my head around it, and a supply of easy examples would appreciated.

Answer 1

Recursion solves part of a problem each "iteration". It requires a base case, when to stop. The partial solutions can be assembled as the recursion "unwinds".

Here's a simple, recursive function to convert a decimal (base 10) integer to any base between 2 and 35:

characters = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"

def mkDigit( number, base ):
if( number == 0 ):
return ""
index = number % base
number = number // base
return mkDigit( number, base ) + characters[ index ]

Answer 2

Another Example:
This prints numbers from 10 to 0
n=10
printNumber(n)
{
while(n<0)
{
//Print the Number
print n;
//Decrement the value by 1
n=n-1;
//Calling the Recursive function
printNumber(n);
}
}