一百万以内的素数

#include <iostream>
#include <vector>
using namespace std;
#define MAX 1000000

long s[MAX+1];

void init()//构造一个100万以内的素数表
{
   int i, j;
   for (i = 2; i <= MAX; i++)
   {
       s[i] = 1;
   }
   s[0] = s[1] = 0; //0和1肯定不是素数

   for (i = 2; i <= MAX; i++)
   {
       if (s[i] == 1)
       {
           for (j = 2 * i;  j <= MAX; j += i)
               s[j] = 0;
       }
   }
}

int main()
{
    init();//构造一个100万以内的素数表
    long a, b;
    int tmp = 0;
    int i, j;
    vector<int> vec;

 	while (cin >> a >> b)
 	{
 	    for (i = a; i <= b; i++)
 	    {
 	        if (s[i] == 1)
 	           tmp++;
 	    }
 	    vec.push_back(tmp);
 	    tmp = 0;
    }

    i = 1;
    for (vector<int>::iterator it = vec.begin(); it != vec.end(); it++)
 	{
	 	cout << "Case " << i++ << ":" << endl;
	 	cout << *it << endl;
	}

 	//system("pause");
 	return 0;
}