## C O D E

**CODE:**

**CODE:**

#include <stdio.h>

int fibonacci(int n) {

if (n <= 1) {

return n;

} else {

return (fibonacci(n – 1) + fibonacci(n – 2));

}

}

int main() {

int n;

printf(“Enter the number of terms you want in the Fibonacci series: “);

scanf(“%d”, &n);

printf(“Fibonacci Series: “);

for (int i = 0; i < n; i++) {

printf(“%d “, fibonacci(i));

}

return 0;

}

**OUTPUT:**

Enter the number of terms you want in the Fibonacci series: 10

Fibonacci Series: 0 1 1 2 3 5 8 13 21 34

**FOR COPY PASTE DOWNLOAD CODE FROM HERE:**

#### Table of Contents

## P R O G R A M M I N G

## E X E C U T E

## E X P L A N A T I O N

##### Understanding Series Generation in C Using Recursion

###### Introduction: It is a simple program that generates the Fibonacci series using recursion. The Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones. In this code, we have a recursive function `fibonacci`

that calculates the nth Fibonacci number, and a `main`

function to control the user interface and program flow.

Code Explanation:

**Header Inclusion****#include <stdio.h>**

This line includes the standard input/output library, which is necessary for using functions like

`printf`

and`scanf`

.**Recursive Fibonacci Function****int fibonacci(int n) {**

**if (n <= 1) {**

**return n;**

**} else {**

**return (fibonacci(n - 1) + fibonacci(n - 2));**

**}**

**}**

`fibonacci`

is a recursive function that calculates the nth Fibonacci number.- It takes an integer
`n`

as input and returns an integer as the result. - The base case of the recursion is when
`n`

is less than or equal to 1. In this case, it returns`n`

(0 for n=0 and 1 for n=1), as the Fibonacci series starts with 0 and 1. - For
`n`

greater than 1, it recursively calls itself with`n - 1`

and`n - 2`

, sums the results of these recursive calls, and returns the sum. This is the essence of the Fibonacci series, where each number is the sum of the two preceding ones.

**Main Function****int main() {**

**int n;****printf(“Enter the number of terms you want in the Fibonacci series: “);**

**scanf(“%d”, &n);****printf(“Fibonacci Series: “);**

**for (int i = 0; i < n; i++) {**

**printf(“%d “, fibonacci(i));**

**}****return 0;**

**}**- The
`main`

function serves as the entry point of the program. - It declares an integer variable
`n`

to store the number of terms the user wants in the Fibonacci series. - It uses
`printf`

to display a message asking the user to enter the number of terms. - It uses
`scanf`

to read the user’s input and store it in the variable`n`

. - It prints the message “Fibonacci Series: ” to indicate that the following numbers are part of the Fibonacci series.
- It uses a
`for`

loop to generate and print the Fibonacci series up to the specified number of terms. Inside the loop, it calls the`fibonacci`

function for each term (from 0 to n-1) and prints the result.

- The

Execution Flow:

- The program starts with the
`main`

function. - The user is prompted to enter the number of terms they want in the Fibonacci series.
- The user inputs a value for
`n`

. - The program enters a loop that iterates from
`i`

= 0 to`i`

= n-1. - For each value of
`i`

, the`fibonacci`

function is called to calculate the ith term in the Fibonacci series. - The result is printed to the console, separated by spaces.
- The loop continues until
`i`

reaches n-1, generating the desired number of terms in the Fibonacci series. - The program terminates.

Key Concepts:

**Recursion**: The`fibonacci`

function uses recursion to calculate Fibonacci numbers. It breaks down the problem into smaller subproblems by calling itself with smaller inputs and combines the results to obtain the final answer.**Base Case**: The base case of the recursion is when`n`

is 0 or 1, where the function returns the corresponding value (0 or 1). Base cases are essential in recursive functions to prevent infinite recursion.**User Input**: The`main`

function handles user input and utilizes the value entered by the user to control the number of terms in the Fibonacci series.**Looping**: A`for`

loop is used to iterate through the values from 0 to n-1, and for each value of`i`

, the corresponding Fibonacci number is calculated and printed.**Printing to Console**: The`printf`

function is used to display messages and print the Fibonacci series to the console.

In summary, the code provided demonstrates a simple implementation of generating the Fibonacci series in C using recursion. It uses a recursive function to compute the Fibonacci numbers, and the `main`

function handles user input and controls the program flow. This code is a fundamental example of recursive programming and is useful for educational purposes.

**MORE PROGRAM :**

**MORE PROGRAM :**

- https://d-techsol.in/in-c-programming-write-a-code-of-lcm-of-two-number/
- https://d-techsol.in/write-a-program-of-addition-of-number-in-c/
- https://d-techsol.in/fibonacci-series-in-c-program-using-for-loop/
- https://d-techsol.in/easy-code-of-factorial-in-c-program/
- https://d-techsol.in/4-factorial-using-recursion-of-a-number-in-c-program/

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