How does "new" work in this C++ function?

Question

int main()
{
    int e[]={3,5,1,2,-2,-1,7,8,0,9};
    int *f;
    int fsize;
   f=smaller_than(e,10,fsize,5);
}

I have a function:

int * smaller_than(const int list[],const int SIZE,int& count,const int THRESHOLD=0)
{
    count = 0;

    for (int i = 0; i < SIZE; i++)
    {
        if (list[i] < THRESHOLD)
        {
            count++;
        }
    }       
    int newArray[count];
    int *p = newArray;
    int j = 0;

    for (int i = 0; i < SIZE; i++)
    {
        if (list[i] < THRESHOLD)
        {
            newArray[j] = list[i];
            j++;
        }
    }
    return p;

Which does not print correctly using a separate printing function, it prints 3 32767 229810164 1 -1 0, but when I copy what another person did:

    int * newArray = new int[count];
    int j = 0;

    for (int i = 0; i < SIZE; i++)
    {
        if (list[i] < THRESHOLD)
        {
            newArray[j] = list[i];
            j++;
        }
    }

    return newArray;
}

this works and prints 3 1 2 -2 -1 0. I don't understand, why didn't mine work properly and what's the difference with using the "new" keyword?