a.txt

来自「铁道出版社出版的C++的习题源代码」· 文本 代码 · 共 46 行

#include<iostream.h>
#include<math.h>
//using namespace std;
int main()
{
	float a,b,c,disc,x1,x2,p,q;
	cout<<"input a,b,c:";
	cin>>a>>b>>c;
	if(a==0)
	  if(b==0)
	     if(c==0)
		cout<<"It is trivial."<<endl;
	     else
		cout<<"It is impossible."<<endl;
	   else
	   {
		cout<<"It has one solution:"<<endl;
		cout<<"x="<<-c/b<<endl;
	   }
	else
	{
		disc=b*b-4*a*c;
		if(disc>=0)
		   if(disc>0)
		   {
			cout<<"It has two real solutions:"<<endl;
			x1=(-b+sqrt(disc))/(2*a);
			x2=(-b-sqrt(disc))/(2*a);
			cout<<"x1="<<x1<<",x2="<<x2<<endl;
		   }
		   else
		   {
			cout<<"It has two complex solutions:"<<endl;
			cout<<"x1=x2="<<-b/(2*a)<<endl;
		   }
		else
		{
			cout<<"It has two complex solutions:"<<endl;
			p=-b/(2*a);
			q=sqrt(-disc)/(2*a);
			cout<<"x1="<<p<<"+"<<q<<"i,x2="<<p<<"-"<<q<<"i"<<endl;
		}
	}
	return 0;
}