# include <stdio.h>
# include <math.h>
main()
{
    float i,j,k;

    for(i=1;i<100;i++)
    {
        k=sqrt(i);
        for(j=2;j<k;j++)
        if(k%i==0)
        {
            break ;
        }

        
    }

}

    2    IntelliSense: 表达式必须具有整数或未区分范围的枚举类型

# include <stdio.h>
# include <math.h>
main()
{
    int i,j,k;

    for(i=1;i<100;i++)
    {
        k=sqrt((double)i);
        for(j=2;j<k;j++)
        if(k%i==0)
        {
            break ;
        }

        
    }

}

/*求100以内的素数*/
#include <stdio.h>

int main()
{
   int i,j;

   for(i=2;i<100;i++)
   {
       for(j=2;j<=i/2;j++)
       {
           if(i%j==0)  break;
       }

       if(j>i/2)  printf("%3d",i);
   }

    return 0;
}

哦哦，谢谢