有句语句不懂，望指教！
#include <stdio.h>
#include <math.h>
void main()
{
    float a,b,c, disc,x1,x2,realpart,imagpart;
    printf("输入a,b,c:");
    scanf("%f,%f,%f",&a,&b,&c);
    if (fabs(a)<=1e-6)//这是什么意思？
        printf("非二次方程");
    else
    {
        disc=b*b-4*a*c;
        if(fabs(disc)<=1e-6)//这里是不是应该为if(fabs(disc)=1e-6)哟?
            printf("有两个相等实数根:\n x1=x2=%8.4f \n",-b/(2*a));
        else
            if(disc>1e-6)
            {
              x1=(-b+sqrt(disc))/(2*a);
              x2=(-b-sqrt(disc))/(2*a);
              printf("有两个实数根:\nx1=%8.4f\nx2=%8.4f\n",x1,x2);
            }
            else
            {
            realpart=-b/(2*a);
            imagpart=sqrt(-disc)/(2*a);
            printf("有两个复根:\n");
            printf("x1=%8.4f+%8.4f\n",realpart,imagpart);
            }
    }

哦，谢谢了。