C program for Fibonacci series

C program to print fibonacci series using iteration 

#include <stdio.h>

int main() {

    int n, i, fib0 = 0, fib1 = 1, fib;

 printf("Enter the number of terms: ");

    scanf("%d", &n);

  printf("Fibonacci Series: ");

  for (i = 1; i <= n; i++) {

        printf("%d ", fib0);

        fib = fib0 + fib1;

        fib0 = fib1;

        fib1 = fib;

    }

    return 0;

}

Explanation:

* The program first prompts the user to enter the number of terms in the Fibonacci series.

* It initializes variables fib0 and fib1 to the first two terms of the series.

* The for loop is used to iterate from 1 to n, and in each iteration, it prints the value of fib0, which is the current term of the series.

* The fib variable is used to calculate the next term of the series by adding fib0 and fib1.

* Then fib0 is updated to the value of fib1, and fib1 is updated to the value of fib, which is the next term of the series.

* After the loop finishes, the program returns 0, indicating successful execution.

Sample Output:

Sample output:

Enter the number of terms: 10

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

         

C program to print fibonacci series with recursion 

#include <stdio.h>

int fibonacci(int n);

int main() {

    int n, i;

    printf("Enter the number of terms: ");

    scanf("%d", &n);

  printf("Fibonacci series:\n");

    for (i = 0; i < n; i++) {

        printf("%d ", fibonacci(i));

    }

return 0;

}

int fibonacci(int n) {

    if (n <= 1) {

        return n;

    }

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

}

Explanation :

* The program starts by including the standard input/output header file stdio.h, which is needed for input/output operations.

* The program defines a recursive function fibonacci(), which takes an integer argument n and returns an integer value. 

* This function is responsible for calculating the n-th term in the Fibonacci sequence.

* The main function starts by declaring some variables: n to store the number of terms in the sequence, and i for use in the loop that will print the sequence.

* The program prompts the user to enter the number of terms they want to print in the Fibonacci sequence, and reads the user's input using the scanf() function.

* The program then prints a message to let the user know that the Fibonacci series is about to be printed.

* The program enters a for loop that will print each term of the sequence up to the number of terms specified by the user. In each iteration of the loop, the program calls the fibonacci() function with the loop counter i as an argument, and prints the result.

* The fibonacci() function is defined recursively: if the argument n is less than or equal to 1 (i.e., if n is 0 or 1), the function simply returns n. Otherwise, the function recursively calls itself with arguments n-1 and n-2, adds the results, and returns the sum.

* Finally, the program returns 0 to indicate successful completion of the main function.

* That's it! When the program is run, it prompts the user to enter the number of terms they want to see in the Fibonacci sequence, calculates the sequence using the fibonacci() function defined recursively, and prints the results.

Sample Output:

Enter the number of terms: 10

Fibonacci series:

0 1 1 2 3 5 8 13 21 34 

The program takes input from the user for the number of terms in the Fibonacci series, and then prints the series using a loop and the fibonacci() function that is defined recursively.

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