void Eratosthenes(int a)
{
int b;
b = int(pow(a, 0.5));
bool judge = true;
for (int i = 2; i <= b; i++)
{
bool judge2 = true;
for (int j = 2; j < i; j++)
{
if (i % j == 0)
{
judge2 = false;
break;
}
}
if (judge2)
{
if (a % i == 0)
{
judge = false;
break;
}
}
}
if (judge)
{
cout << "是素数" << endl;
}
else
{
cout << "不是素数" << endl;
}
}