[help - SPOILERS] sum All Primes - code works but won't pass tests[SOLVED]

1

Hello everyone,

I am having a tough time with the sum All primes algorithm. The code I have returns the correct values on JS bin without any console errors:
js bin - sum all primes

When I run the code on code camp, it throws this error: "potential infinite loop at line 8… " which is where I set “notPrime = false” below. I have tried adding //noprotect as line 1 of code. The code runs and returns the sum, but the test do not pass.

var arr = []; //store prime numbers here

//primeBelow pushes prime numbers <= val into arr array 
function primeBelow(val){
  //test all numbers between 2 and val for prime
  var notPrime;
  for (var numTest = 2; numTest <= val; numTest++){
    notPrime = false;
    //divide i by all numbers below i. 
    //If any division has zero remainder, its not prime.
    for (var i = 2; i<=numTest; i++){ 
      if (numTest%i === 0 && numTest != i){
        notPrime = true;
      }
    }
    //if the prime test is passed, push the value to arr
    if (notPrime === false) {
      arr.push(numTest);
    }
  }
  return arr;
}

//sumPrimes call the primeBelow function and sums all prime values below num
function sumPrimes(num){
  var sum = 0;
  primeBelow(num);
  arr.map(function(val){
      sum += val;
  });
  console.log(arr, sum);
  return sum;
}

sumPrimes(977);

I don’t see where the infinite loop warning is coming from, or what I am missing. :dizzy_face:

Browsers tried: Chromium and Firefox

Any insights would be greatly appreciated. Thanks for reading!

2

I’m not sure of the exact reason why this is the case, but I think it is because you declare the arr outside of the two functions that reference it.

I modified your code slightly and it worked:

Spoiler 
// I deleted the line below:
// var arr = []; //store prime numbers here

function primeBelow(val){
  // I added the arr here:
  var arr = [];
  var notPrime;
  for (var numTest = 2; numTest <= val; numTest++){
    notPrime = false;
    for (var i = 2; i<=numTest; i++){ 
      if (numTest%i === 0 && numTest != i){
        notPrime = true;
      }
    }
    if (notPrime === false) {
      arr.push(numTest);
    }
  }
  return arr;
}

function sumPrimes(num){
  var sum = 0;
  // Notice here I pass the arr variable between the functions 
  // by assigning the return value of the other function to the 
  // arr variable in this function
  var arr = primeBelow(num);
  arr.map(function(val){
      sum += val;
  });
  return sum;
}

sumPrimes(10);
1 Like
3

Thank you jacksonBates! I was banging my head against this wall for too long. I had tunnel vision on that if statement. I never looked at the rest of the code, let alone think that the simple variable declaration could have been the cause.

thanks, and Cheers Sir!:beers: