I think my code is right,but i get unexpected results on big numbers

JavaScript
1

Tell us what’s happening:
So i solved the challenge where i had to find the sum of all previous numbers of the given number.I think my code is wright but i get strange numbers when i pass the 977 number as an example.Can anyone help?

Your code so far


function sumPrimes(num) {
let primesArray=[];
let timesCounter=0;

for(let j=2;j<=num;j++){  //check each previous number if is a prime
  timesCounter=0;  //how many times he will get divided and give 0 are a result
  for(let i=2;i<=num;i++){  
    if(j%i==0){
      timesCounter++;
    }
  }

  if(timesCounter==1) primesArray.push(j) //if he got divided only one time he is a prime
}

let sumOfPrimes = primesArray.reduce((sum,item)=>sum+item,0); //get the sum of all the primes

return sumOfPrimes;
}

sumPrimes(120);

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.83 Safari/537.36.

Challenge: Sum All Primes

Link to the challenge:

2

How are your results different that you expect for large numbers?

3

Notice that the result for func(977) is off by exactly 977.

4

There is an example on wikipedia for prime numbers with number 120.I tried 120 on my funciton,consoled.log the array and it worked fine.But when i go on 977,it is not.I am confused a bit.

5

Oh i just saw on the console that there is a potential infinite loop,test’s may fail.But i dont get it,how there is not an infinite loop when i give the numbers 10 and 121 for an argument but there is when i give 977?
I also run this code on scrimba.com and it works fine with 977 as an argument.

6

Hi,

Here again what is expected in the challenge!

Rewrite sumPrimes so it returns the sum of all prime numbers that are LESS OR EQUAL to num. That means (<= num). It was mentioned by @CactusWren2020

7

i already tried to put <= in my for loop.Still not working.Thanks

8

I restarted the browser and restart the code from the start and it worked.It seems it was just a bug.Thanks for the help!

9

You have to do it for:

for(let i=2; i<=num; i++)

and for:

for(let j=2 ;j<=num; j++)

I have checked that and it works!

1 Like
10

yeah i did it so many times,but it didnt.It was a bug,i fixed by restarting the browser and the challenge.Pfff sorry!

1 Like