screen.cpp

常用算法与数据结构原代码

#include <iostream.h>

#define N 20
#define LN 16

void main()
{
	unsigned int sieve[N],primes[N];
	unsigned int j,w,p,c;
	for (j=0;j<N;j++)
	{
		sieve[j]=0xffff;
		primes[j]=0x0;
	}
	w=0;j=0;
	do{
		while (((0x01<<(j++)) & sieve[w])==0x00)
			;
		p=w*LN+j-1;
		c=2*(p+1)+1;
		primes[w]|=(0x01<<(j-1));
		do{
			sieve[p/LN]&=(~(0x01<<p%LN));
			p+=c;
		}
		while (p<N*LN);
		while ((sieve[w]==0x00) && (w<N-1))
		{
			w++;
			j=0;
		}
	}
	while (sieve[w]);
	cout<<"2  ";
	for (w=0;w<N;w++)
	{
		for (j=0;j<LN;j++)
			if ((0x01<<j) & primes[w])
				cout<<2*(w*LN+j+1)+1<<"  ";
		cout<<endl;	
	}
}