function that call themselves???

[Rakanoth]

Hi again i. Read in the documentation
About function that call themselves
What exactly it mean call themselves
I tried to explore this in google and still dont get it
And also the prototype function
I want to mention again c++ is my first expirience
With programming so my questions might seem a bit
Obvious to guys with expirience

[JLBorges]

http://www.cprogramming.com/tutorial/lesson16.html
http://erwnerve.tripod.com/prog/recursion/index.htm

[vlad from moscow]

It means recursion. For example that to calculate the length of a string you can write the following function

size_t length( const char *s )
{
   return ( *s ? 1 + length( ++s ) : 0 );
}

[Rakanoth]

this look like a "regular" function to me

[3qX21hU5]

Notice how it calls itself in the return statement if a certain condition isn't met.

return ( *s ? 1 + length( ++s ) : 0 );

This is what they mean by a function calling itself and is often referred to as recursion

[Manga]

A function that calls itself is recurision.

viod thismyfunction() {
  cout << "Hi there."<< endl;
  thismyfunction();
}

But that was an example. Don't actually test it. God only knows what it would do.

You can have functions that call themselves for a loop effect.

[giblit]

If you read the documentation about recursion it probably showed an example for finding the factorial of a number something like this

const long long factorial( short n )
{
    return n > 1 ? n * factorial( --n ) : 1; //calls itself multiple times here
}

*edit forgot n *

[Manga]

You guys make beautiful use of the if-else operator here.

Unfortunately... I was only just introduced to that topic today.

Remember kiddos if you aren't speaking in "for dummies" lingo you might as well be speaking in code. :P

[giblit]

Fine let me simplify it

long long int factorial_function( short int n )
{
    if( n > 1 ) return( n - 1 );
    else return( 1 );
}

Edit its also called a ternary operator.
http://en.wikipedia.org/wiki/%3F:
variable = condition ? if_true : if_false;
as in if the condition is true variable = is_true;
if condition is false variable = is_false;

[vlad from moscow]

@giblit

Fine let me simplify it

long long int factorial_function( short int n )
{
    if( n > 1 ) return( n - 1 );
    else return( 1 );
} 

You simplified the function such a way that it has nothing common with the calculation of factorial because it always returns 1.:)

So if to continue your simplification the function can be written simply as

long long int factorial_function( short int )
{
    return( 1 );
} 

[giblit]

whoops I meant n * factorial( n - 1 )...sorry

long long int factorial_function( short int n )
{
    if( n > 1 ) return( n * factorial( n - 1 ) );
    return( 1 );
}