真题解

https://jingyan.baidu.com/article/ca00d56c2e0952e99eebcf86.html

不会一元二次的人一定要看

完整代码如下：

#include <stdio.h>
#include <math.h>
#include <iostream>
using namespace std;
int main()
{
	double x1,x2;
	double a,b,c;
    cin >> a >> b >> c;
    if ((b * b - 4 * a * c) < 0)
    {
        cout<<"No answer!";
    }
    else
    {
        if((b * b - 4 * a * c) == 0)
        {
        	x1 = -1 * (b / (2 * a));
            printf("X1=X2=%.5lf\n",x1);
        }
        else
        {
        	x1 = (-b + sqrt(b*b - 4*a*c))/(2*a);
        	x2 = (-b - sqrt(b*b - 4*a*c))/(2*a);
            if(x1 > x2)
            {
                swap(x1,x2);
            }
            printf("x1=%.5lf;x2=%.5lf\n",x1,x2);
        }
    }

}