题解 | #计算一元二次方程#

#include <cmath>
#include <iostream>
#include <iomanip>
using namespace std;

int main() {
    double a,b,c,del;
    while(cin>>a>>b>>c){
    del=pow(b, 2)-4*a*c;
    if(a==0){
        cout<<"Not quadratic equation";
    }
    else{
        if(del>0){
        cout<<fixed<<setprecision(2)<<"x1="<<(-b-sqrt(del))/(2*a)<<";"<<"x2="<<(-b+sqrt(del))/(2*a)<<endl;
        }
        else  if(del<0){
        cout<<fixed<<setprecision(2)<<"x1="<<(-b)/(2*a)<<"-"<<abs(sqrt((-1)*del)/(2*a))<<"i";
        cout<<fixed<<setprecision(2)<<";x2="<<(-b)/(2*a)<<"+"<<abs(sqrt((-1)*del)/(2*a))<<"i"<<endl;
        }
        else{
          if (-b/(2*a)==0)
          {
            cout<<fixed<<setprecision(2)<<"x1=x2="<<abs(-b/(2*a))<<endl;
          }
          else{
        cout<<fixed<<setprecision(2)<<"x1=x2="<<-b/(2*a)<<endl;
        }
        }
    }
    }
}