请问为什么这个程序不可以，， 就连第一个例子也跑不了，，， 实在是没看出哪里有问题，，， 麻烦了！谢谢！

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


int main()
{
	double a, b, c;
	double delta;
	double x1, x2;
	cin >> a >> b >> c;

	delta = b * b - 4 * a * c;

	if (delta == 0)
	{
		x1 = -b / (2 * a);
		cout << "x1=x2=" << setprecision(5) << ios::fixed << x1;
	}
	else if (delta>0 )
	{
		delta = sqrt(delta);
		x1 = (-b - delta) / (2 * a);
		x2 = (-b + delta) / (2 * a);

		if (x1 > x2)
		{
			swap(x1, x2);
		}
		cout << "x1=" << setprecision(5) << ios::fixed << x1 << ";"
			<< "x2=" << setprecision(5) << ios::fixed << x2;

	}
	else cout << "No answer!";
	return 0;
}