Fibonacci Series Using Recursion in C

Introduction

In this lab, you will learn how to create a C program to print the Fibonacci series using recursion. A Fibonacci series is defined as a series in which each number is the sum of the previous two numbers with 1, 1 being the first two elements of the series.

Create a new C file

Create a new C file named main.c in the ~/project/ directory.

Include necessary libraries

Include the necessary standard input/output library stdio.h.

#include<stdio.h>

Define `printFibo` function

Define a function named printFibo with a parameter aj. It is used to print the Fibonacci series.

void printFibo(int aj)
{
    static long int first = 0, second = 1, sum;
    if(aj > 1)
    {
        sum = first + second;
        first = second;
        second = sum;
        printf("%ld ", sum);
        printFibo(aj-1);    // recursive call
    }
    else
    {
        // after the elements, for line break
        printf("\n\n\n");
    }
}

Define `main` function

Define the main function. Take the input from the user for the total number of elements in the Fibonacci series, and pass it to the printFibo function.

int main()
{
    printf("\n\n\t\tLabEx - Best place to learn\n\n\n");
    int k, n;
    long int i = 0, j = 1;
    printf("Enter the length of the Fibonacci series: ");
    scanf("%d", &n);
    printf("\n\nFirst %d terms of the Fibonacci series are:\n\n\n",n);
    printf("%d ", 1);
    printFibo(n);
    printf("\n\n\t\t\tCoding is Fun !\n\n\n");
    return 0;
}

Finalize the code

Now, the complete program to print the Fibonacci series using recursion is given below:

#include<stdio.h>

// declaring the function
void printFibo(int);

int main()
{
    printf("\n\n\t\tLabEx - Best place to learn\n\n\n");
    int k, n;
    long int i = 0, j = 1;
    printf("Enter the length of the Fibonacci series: ");
    scanf("%d", &n);
    printf("\n\nFirst %d terms of the Fibonacci series are:\n\n\n",n);
    printf("%d ", 1);
    printFibo(n);
    printf("\n\n\t\t\tCoding is Fun !\n\n\n");
    return 0;
}

void printFibo(int aj)
{
    static long int first = 0, second = 1, sum;
    if(aj > 1)
    {
        sum = first + second;
        first = second;
        second = sum;
        printf("%ld ", sum);
        printFibo(aj-1);    // recursive call
    }
    else
    {
        // after the elements, for line break
        printf("\n\n\n");
    }
}

Summary

In this lab, you have learned how to create a C program to print the Fibonacci series using recursion. You now understand the process of defining functions and utilizing recursion to iterate through the necessary series.

Fibonacci Series Using Recursion