5-2筛法求素数.cpp

下楼问题

//5-2 求100以内的素数
#include<iostream.h>
#include<math.h>
void main()
{
	int c,d,k,prime[101];
	for (c=2;c<=100;c++)
		prime[c]=0;
	d=2;
	do
	{
		k=d;
		if (prime[k]==0)
		{
			k=k+d;
	  	 while (k<=100)
		 {
			prime[k]=1;
			k=k+d;
		 }
		}
		d=d+1;
		}while (d<=sqrt(100));
	for (c=2;c<=100;c++)
	{
		if (prime[c]==0)
			cout<<c<<endl;
	}
}