一元二次方程

图片.png
图片.png

注意a为0的情况。

#include <stdio.h>
#include <iostream>
#include <math.h>
using namespace std;

class Mul{
public:
    int a,b,c;
public:
    int getRes(int aa,int bb,int cc,double &flag1,double &flag2){
        a = aa;
        b = bb;
        c = cc;
        double delta; 
        delta = b*b*1.0-4*a*c*1.0;
        if (delta < 0)
        {
            flag1 = -1;
            flag2 = -1;
            return -1;
        }
        else if (fabs(delta)<1E-8)//算delta==0
        {
            flag1 = (-b*1.0/(2.0*a));
            flag2 = (-b*1.0/(2.0*a));
            return 0;
        }
        else//delta > 0
        {
            flag1 = (-b*1.0+sqrt(delta))/(2.0*a);
            flag2 = (-b*1.0-sqrt(delta))/(2.0*a);
            return 1;
        }
    }
    double getRes2(int bb,int cc){
        return -(cc*1.0)/(bb*1.0);
    }
};


int main()
{   
    int m;
    int a,b,c;
    double flag1,flag2;
    Mul M;
    cin >> m;
    for (int i=0;i<m;i++)
    {   
        cin >> a >> b >> c;
        if (a==0)
        {
            printf("x=%.2f\n",M.getRes2(b,c));
        }
        else
        {
            switch (M.getRes(a,b,c,flag1,flag2))
            {
            case -1:printf("%d\n",-1); break;
            case 0: printf("x=%.2f\n",flag1);break;
            case 1: printf("x1=%.2f,x2=%.2f\n",flag2,flag1);break;
            default: break;
            }
        }

    }
    return 0;
}