Page 173 - DCAP407_DATA_STRUCTURE

Data Structure

9.3.2 Fibonacci Series
Fibonacci series is a series of numbers represented as 0, 1, 1, 2, 3, 5, 8, 13, 21, …. Fibonacci series starts
with 0 and 1. Each of the subsequent Fibonacci number is computed as the sum of the previous two
Fibonacci numbers.

Did you know? The ratio of consecutive Fibonacci numbers is equal to 1.618. This repeatedly occurs in
nature. This number has been termed as golden ratio or golden mean. Architects often
design buildings, rooms and windows whose width and length are in ratio of the
golden mean.
Fibonacci series is defined recursively as:
fibonacci (0) = 0
fibonacci (1) = 1

fibonacci (n) = fibonacci (n-1) + fibonacci (n-2)
Let us calculate recursively the n Fibonacci number using Fibonacci () function.
th
Program to calculate recursively the n fibonacci number using
th
fibonacci () function.
/* Recursive fibonanacci function */

/* A preprocessor directive to include standard input and output operations */
# include <stdio.h>
/* Globally declare the fibonacci function */
long fibonacci (long n);
/* Main function */
int main (void)
{

/*Declare a long variable named result */
long result;
/*Declare a long variable named number */
long number;
printf (“Input an integer: “);
/* Accept a long variable number */

scanf (“%d”, & number);
/* Fibonacci function is called and its value is stored in a variable named result */
result = fibonacci (number);
/* Print the value of result */
printf (“Fibonacci (%1d) = %ld\n”, number, result);
/* Return 0 */
return 0;
}

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