Fibonnaci

[MARQUITOS51]

Im trying to find any code in C developed to calculate the fibonnacci
series with or without functions. I need a code example so I can
studied and see how it works.

 

[Jordan Abel]

Im trying to find any code in C developed to calculate the fibonnacci
series with or without functions. I need a code example so I can
studied and see how it works.

If you're cheating on homework, ask for something less obvious than code
examples.

#include <math.h>

double fibon(double n) {
return (
pow(1.6180339887498948482045868343656381177203L,n)
-
pow(-.6180339887498948482045868343656381177203L,n)
)/2.2360679774997896964091736687312762354406L;
}

Good luck explaining to your instructor how this works.

[If you're not, you'll need to give people more to work with to show
that you understand the problem and also give your best effort and show
what code you've tried that doesn't work]

 

[Richard Heathfield]

MARQUITOS51 said:

Im trying to find any code in C developed to calculate the fibonnacci
series with or without functions. I need a code example so I can
studied and see how it works.

The Fibonacci series can be defined as f(0) = 0, f(1) = 1, and f(n) = f(n -
1) + f(n - 2) for n > 1.

So it goes like this: 0, 1, 1, 2, 3, 5, 8, 13, etc.

Think about how you would implement this recursively. Hint: look at the
above definition.

Write it. See how slow it is? Find out why. Hint: use printf.

Now think about how you could make it a lot faster. Hint: think about
arrays.

Now see if you can avoid the need for an array by writing this iteratively
instead of recursively.

 

[Suman]

MARQUITOS51 said:

Im trying to find any code in C developed to calculate the fibonnacci
series with or without functions. I need a code example so I can
studied and see how it works.

[...]
Now see if you can avoid the need for an array by writing this iteratively
instead of recursively.

Do you mean Q-Matrix? If not, that's one more thing the OP might want
to check
out.

 

[Jordan Abel]

Write it. See how slow it is? Find out why. Hint: use printf.

Now think about how you could make it a lot faster. Hint: think about
arrays.

All that's needed to change the worst-case performance to linear is a
two-element cache.

 

[buda]

All that's needed to change the worst-case performance to linear is a
two-element cache.

I think Richard tryed to explain the process... how to move from a top down,
recursion-based solution to a memoized recursion, and then to a bottom-up
solution (building that same array that was used for memoization from 0 to
n). This is infact the best you can do if you need to keep all of the first
n Fibonacci numbers - it is unclear if the OP needs this, or he just wants
to write them out. Also, your comment is covered in the last "idea" Richard
gives.