This C Program prints the fibonacci of a given number using recursion. In fibonacci series, each number is the sum of the two preceding numbers. Eg: 0, 1, 1, 2, 3, 5, 8, …
The following program returns the nth number entered by user residing in the fibonacci series.

Here is the source code of the C program to print the nth number of a fibonacci number. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

/*
* C Program to find the nth number in Fibonacci series using recursion
*/
#include <stdio.h>
int fibo(int);

int main()
{
int num;
int result;

printf("Enter the nth number in fibonacci series: ");
scanf("%d", &num);
if (num < 0)
{
printf("Fibonacci of negative number is not possible.\n");
}
else
{
result = fibo(num);
printf("The %d number in fibonacci series is %d\n", num, result);
}
return 0;
}
int fibo(int num)
{
if (num == 0)
{
return 0;
}
else if (num == 1)
{
return 1;
}
else
{
return(fibo(num - 1) + fibo(num - 2));
}
}

$ cc pgm9.c
$ a.out
Enter the nth number in fibonacci series: 8
The 8 number in fibonacci series is 21

$ a.out
Enter the nth number in fibonacci series: 12
The 12 number in fibonacci series is 144