求解二次函数

代码如下：

//二次函数求解
# include<stdio.h>
# include<math.h>
float a,b,c;
struct d{
    double x1;
    double x2;
};
d R;
d func1(float,float,float);
double func2(float,float);
d func3(float,float,float);
int main()
{
    scanf("%f%f%f",&a,&b,&c);
    if(fabs(a)<1e-6)
    {
        printf("非二次函数
");
        return 0;
    }
    if(pow(b,2)-4*a*c>0)
    {
        printf("x1=%7.2f
x2=%7.2f
",func1(a,b,c).x1,func1(a,b,c).x2);
    }
    else if(fabs(pow(b,2)-4*a*c)<1e-6)
    {
        printf("x1=x2=%7.2f
",func2(a,b));
    }
    else
    {
        printf("x1=%7.2f+%7.2fi
x2=%7.2f-%7.2fi
",func3(a,b,c).x1,func3(a,b,c).x2,func3(a,b,c).x1,func3(a,b,c).x2);
    }

    return 0;
}

d func1(float a,float b,float c)
{
    d r;
    double p1=-b/(2.0*a);
    double p2=sqrt(pow(b,2)-4*a*c)/(2.0*a);
    r.x1=p1+p2;
    r.x2=p1-p2;
    return r;
}

double func2(float a,float b)
{
    return -b/(2.0*a);
}

d func3(float a,float b,float c)
{
    d r;
    double p1=-b/(2.0*a);
    double p2=sqrt(-(pow(b,2)-4*a*c))/(2.0*a);
    r.x1=p1;
    r.x2=p2;
    return r;
}

运行结果：