8 #include<stdio.h>
#include<math.h>
#define EPS 1e-6
void main()
{
double a,b,c,d;
printf("输入一元二次方程a= , b= , c=\n");
scanf("a=%lf,b=%lf,c=%lf",&a,&b,&c);
d=b*b-4*a*c;
if(a==EPS)
{
if(b==EPS)
{
if(c==EPS)
printf("0==0参数对方程无意义!");
else
printf("c!=0方程不成立");
}
else
printf("x=%0.2f\n",-c/b);
}
else
if(d>=EPS)
{
printf("x1=%0.2f\n",(-b+sqrt(d))/(2*a));
printf("x2=%0.2f\n",(-b-sqrt(d))/(2*a));
}
else
{
printf("x1=%0.2f+%0.2fi\n",-b/(2*a),sqrt(-d)/(2*a));
printf("x2=%0.2f-%0.2fi\n",-b/(2*a),sqrt(-d)/(2*a));
}
}
}