解一元二次方程的C++实现

一元二次方程的根的情况分为实根与虚根两种,代码如下

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

float *solve_equ(float, float, float);//a, b, c
int main()
{
    float a, b, c;
    cout << "enter a, b, c : " << endl;
    cin >> a >> b>>c;
    float *p = solve_equ(a, b, c);
    if (*p == )
    {
        cout << "x1= " << *(p + ) << endl;
        cout << "x2= " << *(p + ) << endl;
    }
    else if (*p = )
    {
        cout << "x1= " << *(p + ) <<"+"<< *(p + ) << 'i' << endl;
        cout << "x2= " << *(p + ) << *(p + ) << 'i' << endl;
    }
    else cout << "False!\n";

    system("pause");
    return ;
}
float *solve_equ(float a, float b, float c)
{
    float delta = b * b -  * a*c;
    float x1, x2, v1, v2, r; //v stands for virtual part; r stands for real part
    float *t;
    if (delta >= )
    {
        int flag=; //to tell the different kinds of solutions;
        x1 = float(-b + sqrt(delta)) / float( * a);
        x2 = float((-b - sqrt(delta))) / float(( * a));
        t = (float *)malloc(sizeof(float) * );
        *t = flag;
        *(t+) = x1;
        *(t+) = x2;
        return t;
    }
    else
    {
        int flag=;
        r = float(-b) / float( * a);
        v1 = float(sqrt(-delta)) / float( * a);
        v2 = -v1;
        t = (float *)malloc(sizeof(float) * );
        *t = flag;
        *(t+) = r;
        *(t+) = v1;
        *(t+) = v2;
        return t;
    }
}