//  Creating variables to use later
var cORp;
var primeNums = [];
var compNums = [];

// Create numberSieve function
function numberSieve(x) {

    // 0 and 1 are not prime or composite
    if (x < 2 && x >= 0) {
        cORp = 'neither';
    }

    // All negative numbers are composite
    else if (x < 0) {
        cORp = 'composite';
    }

    // Sieve for positive numbers above 1
    else {

        // Some more variables for later use
        possibleFactors = [];
        zFactors = [];
        matchingFactors = [];

        // Takes all numbers that are half of x and below because they are possible factors
        for (i=2; i < x/2+1; i++) {
            possibleFactors.push(i);
        }

        // Takes all possible factors and divides x by them
        for (i=0; i < possibleFactors.length; i++) {
            z = x/possibleFactors[i];
            zFactors.push(z);
        }

        // Checks if the x divided by the possible factors is equal to any of the other possible factors
        for (i in possibleFactors) {
            if (zFactors.indexOf(possibleFactors[i]) !== -1) {
                matchingFactors.push(possibleFactors[i]);
            }
        }

        // Checks if there are any matching factors
        if (matchingFactors.length !== 0) {
            cORp = 'composite';
        }
        else {
            cORp = 'prime';
        }
    }

    // Prime numbers go to one array, Composite numbers go to another
    if (cORp === 'prime') {
        primeNums.push(x);
    }
    else if (cORp === 'composite') {
        compNums.push(x);
    }
}

// For each number 0-100 runs the sieve
a=0;
while (a <= 100) {
    numberSieve(a);
    a++;
}

// Prints out the prime number and composite number arrays
console.log("Prime Numbers: " + primeNums);
console.log("Composite Numbers: " + compNums);