C Program to find the Sum of Fibonacci Series

This section shows how to write a C program to find the sum of Fibonacci series numbers using a while loop. In this example, the whole loop iterates numbers from 0 to n to print Fibonacci numbers and find the sum of those values.

#include<stdio.h>
 
int main()
{
   int Number, First = 0, Second = 1, Next = 0, sum = 0;
 
   printf("Enter Maximum Number for Fibonacci Series = ");
   scanf("%d", &Number);
 
   printf("First %d Fibonacci Series Numbers:\n", Number);
 
   while( First <= Number)
   {
      printf("%d ", First);
      sum = sum + First;
      Next = First + Second;
      First = Second;
      Second = Next; 
   }
   printf("\nThe Sum of Fibonacci Series Numbers = %d\n", sum);
}

C program to find the Sum of the Fibonacci Series Numbers using for loop

In this program to find the Sum of the Fibonacci Series, we have replaced the while loop with the For Loop.

#include <stdio.h>
int main()
{
	int Number, Next, Second = 1, sum = 0;

	printf("\n Please Enter the Range Number: ");
	scanf("%d",&Number);
	
	for(int First = 0; First <= Number;) 
	{
		printf("%d ", First);
      	        sum = sum + First;
      	        Next = First + Second;
		First = Second;
      	        Second = Next; 
	}
	printf("\nThe Sum = %d\n", sum);
}

 Please Enter the Range Number: 25
0 1 1 2 3 5 8 13 21 
The Sum = 54

In this example, the fibonacciSeries recursive function calculates the sum of Fibonacci series numbers by calling it recursively.

#include<stdio.h>

int fibonacciSeries(int Number)
{
   if ( Number == 0 )
      return 0;
   else if ( Number == 1 )
      return 1;
   else
      return ( fibonacciSeries(Number - 1) + fibonacciSeries(Number - 2) );
} 
 
int main()
{
   int Number, i = 0, j, sum = 0;
 
   printf("\nEnter Maximum Number = ");
   scanf("%d", &Number);
 
   printf("Fibonacci Series Numbers up to %d:\n", Number);
 
   for ( j = 0 ; j < Number; j++ )
   {
      printf("%d   ", fibonacciSeries(j));
      sum = sum + fibonacciSeries(j);
   }
     printf("\nThe Sum = %d\n", sum);
}

Enter Maximum Number = 20
Fibonacci Series Numbers up to 20:
0   1   1   2   3   5   8   13   21   34   55   89   144   233   377   610   987   1597   2584   4181   
The Sum = 10945