Find Sum of Fibonacci Series using C, C++ Code

Write a C, C++ program to print sum of Fibonacci Series. Given a positive integer n, print the sum of Fibonacci Series upto n term.

Let's first brush up the concept of Fibonacci series.

Fibonacci series 

In Fibonacci series, the first two numbers are 0 and 1 , and the remaining numbers are the sum of previous two numbers.

Suppose, if input number is 4 then it's Fibonacci series is 0, 1, 1, 2. Now, we are finding sum of Fibonacci series so the output is  4 ( 0 + 1 + 1 + 2).

Let's take another example, this time n is 8 ( n = 4). Then the output is 33 ( 0 + 1 + 1 + 2 + 3 + 5 + 8 + 13).

Print Fibonacci series using iterative approach

Print Fibonacci series using recursion

Program to Find Sum of Fibonacci Series - C Code

#include <stdio.h>
 
int main(void) {
 
   int i, n, first = 0, second = 1, sum = 1, third;
 
   printf (" Enter the range \n");
   scanf( "%d", &n);
 
   for(i = 2; i < n; i++){
 
     /* Sum of previous two element */
 
     third = first + second;
 
     sum = sum + third;
 
     first = second;
     second = third;
 
   }
 
   printf("Sum of Fibonacci series for given range is %d", sum);
 
   return 0;
}
 

Find Sum of Fibonacci Series - C++ Code

#include <iostream>
using namespace std;

int main() {

    int i, n, first = 0, second = 1, sum = 1, third;
 
    cout << " Enter the range \n";
    cin >> n;
 
   for(i = 2; i < n; i++){
 
     /* Print the sum of previous two element */
 
     third = first + second;
 
     sum = sum + third;
 
     first = second;
     second = third;
 
   }
 
   cout << "Sum of Fibonacci series for given range is " << sum;
 
   return 0;
}

Output :

Enter the range : 8

Sum of Fibonacci series for given range is : 33


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