关于获取素数 一个小程序

</pre><pre code_snippet_id="483066" snippet_file_name="blog_20141012_3_4972174" name="code" class="cpp">#include <stdio.h>
#include<math.h>
#define N 101
int main(){
  int i, j, line, a[N];
  for (i = 2; i < N; i++)
    a[i] = i;
  for (i = 2; i <sqrt(double(N)); i++)//sqrt内部要用double型因此要强制转换
  {
    for (j = i + 1; j < N; j++)
    {
      if (a[i]!= 0 && a[j]!= 0)//排除跟自身相等的素数
        if (a[j] % a[i] == 0)


          a[j] = 0;//假设能除尽则把a[i]换为0
    }
  }
  for (i = 2 ,line = 0; i < N; i++)
  {
    if (a[i] != 0)
    {
      printf("%5d",a[i]);
      line++;
    }
    if (line == 10)
    {
      printf("\n");//每十个数换一次行
      line = 0;
    }

  }
  printf("\n");
  return 0;
}