Thread: Fibonacci series using a recursive function

Hello all this my first post, so bear with me if I don't do something correctly.

This is my question: below I have the format for my recursive function but am really unsure of what I need to put in the Underscore areas ?

If anyone has any ideas, I have never done a Fibonacci series of numbers before, so I'm lost as to how it has to be set up.

#include <iostream>
using namespace std;

unsigned long fib(int nth);

void main()
{
int nth=0;

cout << "Enter an integer from 1 to 30: ";

while (!(cin >> nth))
{
cin.clear();
while (cin.get() != '\n')
continue;
cout << " Please! Enter a number: ";
}
if((nth < 1) || (nth > 30))
cout << "\nSorry. "
<< "Number isn't in the right range.";
else
{
unsigned long fibValue;
fib(int fibValue);

cout << "\nThe value of number " << nth;
cout << " in the series is " << fibValue
<< ".\n";
}
}

// Recursive function
unsigned long fib(int nth)
{
if(______)
return(___);
else
return(_________ + ____________);
}

Straight recursive fib is horribly inefficient, this method will probably impress your teachers

Code:

unsigned long fibValue (unsigned long n)
{
    static fibVals[MAX_FIB_VAL] = {0}

    if (n == 0 || n == 1)
        return fibVals[n] = n;
    else if (fibVals[n] == 0)
        return fibVals[n] = fibValue(n-1) + fibVal(n-2);
    // else
    return fibVal[n];
}

Since this code doesnt branch uncontrollably, it will work for much larger numbers

I thank you all for the replies