第八章T1

#include <iostream>

#include <cmath>

using namespace std;

double q(double,double,double);

void main()

{double a,b,c,p,x1,x2;

 cout<<"please enter a,b,c:";

 cin>>a>>b>>c;

 p=-b/(2*a);

 try

 {x1=p+q(a,b,c);

  x2=p-q(a,b,c);

  cout<<"x1="<<x1<<endl<<"x2="<<x2<<endl;

  }

 catch(double d)

  {cout<<"a="<<a<<",b="<<b<<",c="<<c<<",disc="<<d<<",error!"<<endl;}

 cout<<"end"<<endl;

}

 

double q(double a,double b,double c)

 {double disc;

 disc=b*b-4*a*c;

  if(disc<0) throw disc;

 return sqrt(disc)/(2*a);

 }