smeloa - 1 year ago 92

Javascript Question

So I am trying to develop a formula that will sum all odd Fibonacci numbers up to and including a given number.

For example:

- Given number is 4. Then result should be 5 (Odd Fibonacci numbers being 1, 1, 3).

Currently this is my code:

`function sumFibs(num) {`

var sum = 0;

for(i=0,j=1,k=0; k<=num;i=j,j=x,k++) {

x = i + j;

if (x%2 !== 0) {

sum +=x;

if (sum >= sum) {

break;

}

}

}

return sum;

}

sumFibs(4);

Clearly the code doesn't work. If I remove the (if sum >= sum) break statement it creates an infinite loop. I have taken the for loop from another post here where a formula was given to create a Fibonacci sequence, but I am having difficulty with what to do after that number is generated, how do I add it. My way of trying to do this is by checking if the modulus is not 0 (which indicates it is an odd number).

Thanks for your help.

Answer Source

your code is a bit confusing with the variables names and declaration (always try to declare using var). here's a function that gets what you need

```
function sumFibs(num) {
var fib0 = 0;
var fib1 = 1;
var fib = 1;
var sum = fib0;
while ( fib <= num){
if (fib % 2) {
sum += fib1;
}
fib = fib0 + fib1;
fib1 += fib0;
fib0 = fib1 - fib0;
}
return sum;
}
```