输入系数a、 b、 c, 求解一元二次方程ax2+bx+c=0的根

#include<iostream>

using namespace std;

#include<cmath>

 int main()

 {

  float a,b,c;

  double x1,x2,s;

  cout<<"please enter the num：";

  cin>>a>>b>>c;

  if(b*b-4*a*c>=0)

{

x1=(-b+sqrt(b*b-4*a*c))/(2*a);

  x2=(-b-sqrt(b*b-4*a*c))/(2*a);

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

}

else

cout<<"方程无实根"<<endl; 

  return 0;

 }