输出素数

给定一个正整数n，要求输出n以内所有的素数。

void primeNum(int n){    bool *prime = new bool(n+1);    memset(prime, true, n*sizeof(bool));    prime[0] = false;    prime[1] = false;    int limit = sqrt(n);    for (int i = 2; i <= limit; i++)    {        if (prime[i])        {            for (int j = i*i; j <=n; j += i)            {                prime[j] = false;            }        }    }    for (int i = 0; i <= n; i++)    {        if (prime[i])        {            cout << i << " ";        }    }    cout << endl;    delete []prime;}