Go4Expert (http://www.go4expert.com/)
-   C++ (http://www.go4expert.com/forums/cpp/)
-   -   Simple factorial function in C++ :D (http://www.go4expert.com/forums/simple-factorial-function-cpp-d-t16145/)

 TriG0rZ 11Feb2009 16:01

Simple factorial function in C++ :D

Basiclly what im trying to to (and not for uni but for someone else) is to try and create a function to take a interger from a user and find the factorial of is.

Factorial being :

The factorial of 2 is:
2x1=2
The factorial of 9 is:
9 x 8x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 720

So far i can do:

int num;

cin<< num;

now i need the funcation to somehow do the factoril bit :P

this being a error trap saying if the answer is <=0 then jsut return 0

if(numfac==>0)
{

cout>>numfac;
else
cout<<0;
}

So if anyone can help in being able to do the function bit that would be amazingly helpfull thanks sexy people :D

(ignore any mistakes i just that bit on the spot lol)

 xpi0t0s 11Feb2009 18:37

Re: Simple factorial function in C++ :D

Write a function that calculates the given number multiplied by that number minus one.
Ensure for 1 and less it returns a suitable value.
Make sure it is fully debugged before you go on to the next step and that some test values return the correct result, e.g. 1->1, 3->6, 6->30, 12->132 (remember at this point all it is calculating is n*(n-1).

Then instead of "that number minus one", just call the function from within itself with "that number minus one" as the given number.

Easy!

Code:

```int f(int n) { ... // recursive call int something=someval*f(n-1); ... return what? }```

 TriG0rZ 12Feb2009 15:49

Re: Simple factorial function in C++ :D

ah yes i can see what you mean xpi0t0.....thanks for the help almost there :D

 yashlodha 14Feb2011 07:00

Re: Simple factorial function in C++ :D

Code:

```//Aim: to Find Factorial Of a No. Using function #include<iostream.h> #include<conio.h> long int fact(int); void main() {         int n;         long int f=1;         clrscr();         cout<<"\n enetr a value:";         cin>>n;         f=fact(n);         cout<<"\n the factorial is:"<<f;         getch(); } long int fact(int m) {         int i;         long int f=1;         for(i=1;i<=m;i++)         {         f=f*i;         }         return(f); }```

 xpi0t0s 14Feb2011 15:45

Re: Simple factorial function in C++ :D

And did you feel the need to inform the entire Tour de France team when you finally stopped falling off your bike?

 All times are GMT +5.5. The time now is 20:00.