Bonfire Sum All Odd Fibonacci Numbers

Author

Created by Rafase282

Github | FreeCodeCamp | CodePen | LinkedIn | Website | My Original Wiki

Details

• Difficulty: 2/5

Return the sum of all odd Fibonacci numbers up to and including the passed number if it is a Fibonacci number. The first few numbers of the Fibonacci sequence are 1, 1, 2, 3, 5 and 8, and each subsequent number is the sum of the previous two numbers. As an example, passing 4 to the function should return 5 because all the odd Fibonacci numbers under 4 are 1, 1, and 3.

Remember to use RSAP if you get stuck. Try to pair program. Write your own code.

Useful Links

• Remainder
• Fibonacci Numbers

Problem Script:

function sumFibs(num) {
  return num;
}

sumFibs(4);

Explanation:

You will need to gather all the Fibonacci numbers and then check for the odd ones. Once you get the odd ones then you will add them all. The last number should be the number given as a parameter if it actually happens to be an off Fibonacci number.

Hint: 1

To get the next number of the series, you need to add the current one to the previous and that will give you the next one.

Hint: 2

To check if a number is even all you have to check is if that number % 2 == 0.

Hint: 3

As you get the next odd one, don't forget to add it to a global variable that can be returned at the end. result += currNumber; Will do the trick.

My code:

function sumFibs(num) {
    var prevNumber = 0;
    var currNumber = 1;
    var result = 0;
    while (currNumber <= num) {
        if (currNumber % 2 !== 0) {
            result += currNumber;
        }
        var added = currNumber + prevNumber;
        prevNumber = currNumber;
        currNumber = added;
    }

    return result;
}

My Code Explanation:

• Create a variable to keep record of the current and previous numbers along with the result that will be returned.
• Use a while loop to make sure we do not go over the number given as parameter.
• We use the modulo operand to check if the current number is odd or even. If even add it to the result.
• Complete the Fibonacci circle by rotating getting the next number and swapping values after.
• Return the result.

Go Home