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Recursion
Recursion is a programming technique
that can accomplish a lot with a little bit of code. Because recursive
procedures call themselves, their operation seems like magic. Here
are a couple of recursive functions - one to calculate factorials and one
to calculate Fibonacci numbers.
Example 1: Factorials
N factorial for a positive integer N is
defined as the product of the integers 1 through N. It is usually written
as N!.
Function
factorial(N:integer):Integer;
Begin
If N=1 then result:=1
else result:=N*factorial(N-1);
end;
Example 2: Fibonacci Numbers
Fibonacci
numbers are members of an infinite series of integers in which the first two numbers are 1,
and each number after the 2nd is the sum of the two preceding numbers (1, 1, 2,
3, 5, 8, 13....). Here's a
function that returns the Nth Fibonacci number:
Function
Fibonacci(n:integer) :integer;
Begin
If N<=2 then result:=1
else result:=Fibonacci(n-1)+Fibonacci(n-2);
end;
Here is a program that
calculates integer powers of a real number. Recursion is one of 4
techniques tested. The program will also introduce you to techniques for
accurately measuring program run times. Click
here to download source code for IntPowerDemo.
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