text: #include<stdio.h>
  #include<time.h>
  int main()
  {
  	int begin, end;
  	const int f = 999;
  	begin=clock();
  	int y,x,i;
  	x  = 2;
  	y = 1;
  	while (x<=f)
  	{
  		i = 2;
  		while (i <= (x / 2)) 
  		{
  			y = x % i;
  			if (y == 0) 
  			{
  				break;
  			}
  			else
  				i++;
  		}
  			if (y != 0)
  				printf("%d ", x);
  		x++;
  	}
  	end = clock();
  	printf("运行时间为%dms", end - begin);
      return 0; 
  }