Re: [Dev-C++] recursion help

[Fernando L. <fer...@gm...>]

I looked it up in Stan Kelly-Bootle's "The Devil's DP Dictionary" and
I found this:

recursion: see recursion

Now serously, in programming recursion means that a function can call
itself. The power example is a good one, another classic one is to say
that

factorial(n) =3D n * factorial (n - 1)

This could go on endlessly if it were not for the fact that 0! =3D 1, so
a recursive factorial function would call itself until its argument
became 0, where it would return 1 and unwind the chain of calls.

A similar reasoning could be applied to analizing sentences, or
traversing the leaves of a binary tree.

Regards,

On 11/8/05, Robert Alatalo <ral...@gm...> wrote:
> Recursion works by solving a simpler problem.  In the case above you know
> that if you raise any number to the 1st power then you get that number ba=
ck,
>   Otherwise you can get the result by multipling the number by the number
> raised to the initial power minus one.
>
> So if I am going to raise 10 to the third power ie pow(10,3)
>
> pow(10,3)=3D10*pow(10,2)
> pow(10,2)=3D10*pow(10,1)
> pow(10,1)=3D10
>
> So... now backing up as each function returns you get
> pow(10,3)=3D10*10*10
>
>
>
>
> On 11/8/05, Richard Gelling <use...@ya...> wrote:
> > Hi,
> >
> > I am working my way through Sams Teach yourself c++ in 21 days and am
> > having a bit fof difficulty with recursion, could someone explain to me
> > how the following oiece of code works:
> >
> > #ifdef HAVE_CONFIG_H
> > #include <config.h>
> > #endif
> >
> > #include <iostream>
> > #include <cstdlib>
> >
> > using namespace std;
> >
> > int toPowerOf( int , int );
> > int main(int argc, char *argv[])
> > {
> >     int powerOf, number, result;
> >     cout << "\nEnter the number: ";
> >     cin >> number;
> >     cout << "\nEnter the exponential: ";
> >     cin >> powerOf;
> >
> >     result =3D toPowerOf( number, powerOf );
> >
> >     cout << "\nThe result of " << number << "  to the power of " <<
> > powerOf << " is " << result << endl;
> >
> >     return 0;
> > }
> > int toPowerOf( int number, int powerOf )
> > {
> >      if ( powerOf =3D=3D 1 )
> >         return number;
> >      else
> >     {
> >         cout << "number is: " << number << " and the power of is " <<
> > powerOf << endl;
> >         return ( number  * toPowerOf( number, powerOf - 1 ));
> >     }
> >    }
> >
> > If someone could explain how the recusion side workd I would be
> > gratefull, as I don't seem to be getting anywhere.
> >
> > Thanks a lot
> >
> > Richard G.
> >
> >
> >
> >
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--
Fernando Lichtschein
li...@fi...