Sum of numbers from 1 to N which are in Fibonacci Sequence

Given an integer N, the task is to find the sum of numbers from 1 to N which are in Fibonacci sequence. 
First few Fibonacci numbers are 1, 1, 2, 3, 5, 8, 13, 21, 34, ….
Examples:

Input: N = 5 
Output: 12 
1 + 1 + 2 + 3 + 5 = 12
Input: N = 10 
Output: 20 
1 + 1 + 2 + 3 + 5 + 8 = 20 

Approach:

• Loop through all the Fibonacci numbers which are less than N.
• Initialize a sum variable with 0.
• Keep on adding these Fibonacci numbers to get the required sum.

Below is the implementation of the above approach:

C++

// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;

// Function to return the
// required sum
int fibonacciSum(int N)
{

    if (N == 0)
        return 0;

    // Generate all Fibonacci numbers <= N
    // and calculate the sum
    int sum = 0;
    int a = 1, b = 1, c;
    sum += a;
    while (b <= N) {

        sum += b;
        int c = a + b;
        a = b;
        b = c;
    }
    return sum;
}

// Driver code
int main()
{
    int N = 20;
    cout << fibonacciSum(N);

    return 0;
}

Java

// Java implementation of the approach
class GFG
{

// Function to return the
// required sum
static int fibonacciSum(int N)
{

    if (N == 0)
        return 0;

    // Generate all Fibonacci numbers <= N
    // and calculate the sum
    int sum = 0;
    int a = 1, b = 1, c;
    sum += a;
    while (b <= N)
    {

        sum += b;
        c = a + b;
        a = b;
        b = c;
    }
    return sum;
}

// Driver code
public static void main(String[] args)
{
    int N = 20;
    System.out.println(fibonacciSum(N));
}
}

// This code is contributed by Code_Mech.

Python3

# Python3 implementation of
# the approach

# Function to return the
# required sum
def fibonacciSum(N):

    if N == 0:
        return 0

    # Generate all Fibonacci
    # numbers <= N and calculate
    # the sum
    Sum = 0
    a, b = 1, 1
    Sum += a
    while b <= N:

        Sum += b
        a, b = b, a + b

    return Sum

# Driver code
if __name__ == "__main__":

    N = 20
    print(fibonacciSum(N))

# This code is contributed
# by Rituraj Jain

C#

// C# implementation of the approach
using System;

class GFG
{

// Function to return the
// required sum
static int fibonacciSum(int N)
{

    if (N == 0)
        return 0;

    // Generate all Fibonacci numbers <= N
    // and calculate the sum
    int sum = 0;
    int a = 1, b = 1, c;
    sum += a;
    while (b <= N)
    {

        sum += b;
        c = a + b;
        a = b;
        b = c;
    }
    return sum;
}

// Driver code
public static void Main()
{
    int N = 20;
    Console.WriteLine(fibonacciSum(N));
}
}

// This code is contributed by Code_Mech.

PHP

<?php
// PHP implementation of the approach

// Function to return the
// required sum
function fibonacciSum($N)
{
    if ($N == 0)
        return 0;

    // Generate all Fibonacci numbers <= N
    // and calculate the sum
    $sum = 0;
    $a = 1; $b = 1; $c;
    $sum += $a;
    while ($b <= $N)
    {
        $sum += $b;
        $c = $a + $b;
        $a = $b;
        $b = $c;
    }
    return $sum;
}

// Driver code
$N = 20;

echo(fibonacciSum($N));

// This code is contributed
// by Code_Mech.
?>

Javascript

<script>

// Javascript implementation of the approach

// Function to return the
// required sum
function fibonacciSum(N)
{

    if (N == 0)
        return 0;

    // Generate all Fibonacci numbers <= N
    // and calculate the sum
    var sum = 0;
    var a = 1, b = 1, c;
    sum += a;
    while (b <= N) {

        sum += b;
        var c = a + b;
        a = b;
        b = c;
    }
    return sum;
}

// Driver code
var N = 20;
document.write( fibonacciSum(N));

</script>

Output:

33