[Central South University of forestry science and technology] [Chen] ninth week operation triangle exception handling

2、 exception handling   try  Check    throw   Throw out   catch  Capture     
Enter the length of the three sides of the triangle , Find the area of the triangle . When the length of the input edge is less than or equal to 0, Throw out int abnormal , Give a warning and end the procedure .
Or when all three sides are greater than 0, But when you can't form a triangle （ The sum of the two sides is greater than that of the third side ）, Throw out double abnormal , Give a warning and end the program . 

#include<iostream>
#include<cmath>
using namespace std;
class Triangle
{   
	double a;
	double b;
	double c;
	double s;
public:
	double area()
	{
		double l = (a + b + c) / 2;
		if (a <= 0 || b <= 0 || c <= 0 || a + b <= c || b + c <= a || c + a <= b) 
		{
			throw a;
		}else
	    s =sqrt( l * (l - a) * (l - b) * (l - c));
		return s;
	}
	void setput()
	{
		cin >> a;
		cin >> b;
		cin >> c;
	}
	
	int loop()
	{
		try
		{
			while (1)
			{
				cout << area() << endl;
				cin >> a >> b >> c;
			}
		}
		catch (double)
		{
			cout << a << " " << b << " " << c << "this is a wrong" << endl;
		}
		cout << "end" << endl;
		return 0;
	}
};
int main(void)
{
	Triangle tri;
	tri.setput();
	tri.loop();
	system("puase");
	return 0;
}