我是 高手 初学者，能AC就行~

#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;
int main()
{
	double a,b,c,x1,x2;
	cin >> a >> b >> c;
	if(a == 0 || b*b - 4*a*c < 0)
		cout << "No answer!";
	else
	{
		x1 = (-b + sqrt(b * b - 4 * a * c)) / (2 * a);
		x2 = (-b - sqrt(b * b - 4 * a * c)) / (2 * a);
		if(x1 == x2)
			printf("x1=x2=%.5f",x1);
		else
		{
			if(x1 > x2)
				swap(x1,x2);
			printf("x1=%.5f;x2=%.5f",x1,x2);
		}
	}
	
	return 0;
}