求助：求方程 ax^2+bx+c=0 的解

总是显示error，新手一枚，求助

代码如下：

#include <stdio.h>

#include <math.h>

int main()

{

double a,b,c,x1,x2,disc,ddisc,p;

scanf("a = %lf b = %lf c = %lf",&a,&b,&c);

disc = b*b - 4 * a * c;

p = - b / (2*a);

if(fabs(a)<=1e-6)

{

if(fabs(b)<=1e-6) printf("error\n");

else printf("x = %lf\n",-c/b);

}

else 

{

if(fabs(disc)<=1e-6)

printf("x = %8.4lf\n",p);

else 

if(disc>1e-6)

{

ddisc = (sqrt(disc))/(2*a);

x1 = p + ddisc;

x2 = p - ddisc;

printf("x1 = %8.4lf x2 = %8.4lf\n",x1,x2);

}

else 

{

ddisc = (sqrt(-disc))/(2*a);

printf("x1 = %8.4lf + %8.4lfi\n",p,ddisc);

printf("x2 = %8.4lf + &8.4lfi\n",p,-ddisc);

}

}

return 0;

}