I am trying this code
var sum = 0
for (i = 0; i < 2000000; i++) {
function checkIfPrime() {
for (factor = 2; factor < i; factor++) {
if (i % factor = 0) {
sum = sum;
}
else {
sum += factor;
}
}
}
}
document.write(sum);
I am getting this error:
Invalid left-hand side in assignment
Change if(i % factor = 0) to if( i % factor == 0) and remove the function checkIfPrime() inside the for loop.
var sum = 0
for (i = 0; i < 2000000; i++) {
for (factor = 2; factor < i; factor++) {
if (i % factor == 0) {
sum = sum;
}
else {
sum += factor;
}
}
}
document.write(sum);
The function inside the loop is pointless.
it looks like your code outputs wrong result, for example prime numbers below 6 are 2, 3 and 5, their sum is 10, your code outputs 14 in this case. Here is another code which outputs sum of primes below max value:
var sieve = [], primes = [], sum = 0, max = 5;
for (var i = 2; i <= max; ++i) {
if (!sieve[i]) {
// i has not been marked -- it is prime
sum += i;
for (var j = i << 1; j <= max; j += i) {
sieve[j] = true;
}
}
}
console.log(sum);
function sumPrimes(num) {
var sum = 0;
for (var i = 2; i < num; i++) {
if (isPrime(i)) {
sum += i;
console.log(sum);
}
}
return sum;
}
function isPrime(num) {
if (num <= 1) return false;
else if (num <= 3) return true;
else if (num % 2 == 0 || num % 3 == 0) return false;
var i = 5;
while (i * i <= num) {
if (num % i == 0 || num % (i + 2) == 0) return false;
i += 6;
}
return true
}
console.log(sumPrimes(2000000));
Well, I did with 250 otherwise my screen would have frozen. First of you have to single out the prime numbers after placing them inside an empty Array, which I called primeNumbers from 2 to whatever number you want. Then I create a function that would filter the prime numbers and then add them all with a reduce method inside of another variable called sum and return that variable.
var primeNumbers =[];
for(var i = 2; i < 250; i++){
primeNumbers.push(i);
}//for loop
function isPrime(value){
for(var x=2; x< value; x++){
if(value % x===0){
return false;
}
}//for loop
return true;
}//function isPrime to filter
var sum = primeNumbers.filter(isPrime).reduce(function(acc, val) {
return acc + val;
}, 0);
console.log(sum);
when you are using a variable inside the loop you need to declare them. You have two points in this case
Your if (i % factor = 0) is wrong, as pointed by some people above.
Also, you never call the checkIfPrime() method. I don't why you created them. Also, I improved your checkIfPrime() method. Please call sumOfPrimes() method in the code below and it should work. You can modify it according to your need
function sumOfPrimes()
{
var sum =0;
for (var i = 0; i < 2000000; i++)
{
var temp = Math.sqrt(i);
for (var factor = 2; factor < temp; factor++)
{
if (i % factor === 0)
{
sum += factor;
}
}
}
console.log(sum);
}
Try changing this line if (i % factor = 0) {
to
if (i % factor == 0) {
