C++标准异常处理 三角形面积

#include<iostream>> #include<stdexcept> #include<cmath> using namespace std; double area(double a, double b, double c) throw(invalid_argument) { 	if (a <= 0 || b <= 0 || c <= 0) 		throw invalid_argument("不合法：a<=0 || b<=0 || c<=0");//标准异常类构造时需要传递一个const string&类型参数，表明异常原因 	if (a + b <= c || a + c <= b || b + c <= a) 		throw invalid_argument("不合法：a+b<=c || a+c<=b || b+c<=a"); 	double s = (a + b + c) / 2; 	return sqrt(s*(s - a)*(s - b)*(s - c)); }  int main() { 	double a, b, c; 	while (1) 	{ 		cout << "输入三条边长a, b, c= "; 		cin >> a >> b >> c; 		try 		{ 			cout<<"s = " << area(a, b, c)<< endl; 		} 		catch (const std::exception& e) 		{ 			cout << e.what() << endl;//每一个继承自exception的标准异常都带有what方法，用以读取异常原因 		} 	} 	return 0; }