A28430. 运行下面的代码，将出现（ ）。double hmean(double a, double b) { if (a == -b ) throw runtime_error("Runtime error occurred."); return 2.0*a*b/(a + b); } int main() { double x = 10; double y = -10; try { int result …

运行下面的代码，将出现（    ）。

double hmean(double a, double b) {
	if (a == -b )
		throw runtime_error("Runtime error occurred.");
	return 2.0*a*b/(a + b);
}

int main() {
	double x = 10;
	double y = -10;
	
	try {
		int result = hmean(x, y);
		cout << "hmean: " << result << endl;
}
	catch (const runtime_error& e) {
		cout << "Caught: " << e.what() << endl;
	} catch (...) {
		cout << "Caught an unknown exception." << endl;
	}
	return 0;
}