题解 | #计算一元二次方程#

#include<stdio.h>
#include<math.h>
#include<complex.h>
int main()
{
    float a=0.0,b=0.0,c=0.0;
    while(scanf("%f %f %f",&a,&b,&c)!=EOF)
    {
        float Delta=b*b-4*a*c;

     if(a!=0)
     {
     if(Delta>0)
     {
        float x1=(-b+sqrt(Delta))/(2*a);
        float x2=(-b-sqrt(Delta))/(2*a);
        printf("x1=%.2f;x2=%.2f\n",x2,x1);
     }
     else if(Delta==0)
     {
        float x=(-b)/(2*a);
       if (x==0)
       {
        x = 0.00;
        printf("x1=x2=%.2f\n", x);
       }
       else
       printf("x1=x2=%.2f\n",x);
     }
     else
     {
        float complex x1=-b/(2*a)-sqrt(-Delta)/(2*a)*I;
        float complex x2=-b/(2*a)+sqrt(-Delta)/(2*a)*I;
        if (cimag(x1) >= 0)
                printf("x1=%.2f+%.2fi;x2=%.2f+%.2fi\n", creal(x1), cimag(x1), creal(x2), cimag(x2));
        else
                printf("x1=%.2f%.2fi;x2=%.2f+%.2fi\n", creal(x1), cimag(x1), creal(x2), cimag(x2));
     }
     }
    else
    printf("Not quadratic equation");
    }
    return 0;
}