计算二次方程根

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

template<typename T>

bool OutputRoots(const T& a,const T& b,const T& c)

{

    if(0 == a)

    {

        cout << "被除数不能为0！" << endl;

        return -1;

    }

    T d = b*b -4*a*c;

    if(d > 0)   // 两个实根

    {

        float sqrtd = sqrt(d);

        cout << "There are two real roots "

             << (-b+sqrtd)/(2*a) << " and "

             << (-b-sqrtd)/(2*a) << endl;

    }

    else if(d == 0) // 两个根据相等

    {

        cout << "There is only one distinct root "

             << -b/(2*a) << endl;

    }

    else // 两个复根

    {

        cout << "The roots are complex " << endl

             << "The real part is "

             << -b/(2*a) << endl

             << "The imaginary part is "

             << sqrt(-d)/(2*a) << endl;

    }

    return true;

}

int main()

{

    OutputRoots(0,-5,6);

    return 0;

}