谭浩强c++ 异常处理

桃扇骨 2022-05-25 07:51 181阅读 0赞

书上例题14.1

#include <iostream>
    #include <cmath>
    using namespace std;
    
    void main()
    {
    	double triangle(double,double,double);
    	double a, b, c;	
    	cin >> a >> b >> c;
    	try//在try块中包含要检查的函数
    	{
    		while (a > 0 && b > 0 && c > 0)
    		{
    			cout << triangle(a, b, c) << endl;
    			cin >> a >> b >> c;
    		}
    	}
    	catch (double)//用catch捕捉异常信息并作相应处理
    	{
    		cout << "a = " << a << ",b = " << b << ",c = " << c << ",that is not triangle!" << endl;
    	}
    	cout << "end" << endl;
    	system("pause");
    }
    
    double triangle(double a, double b, double c)
    {
    	double s = (a + b + c) / 2;
    	if (a + b <= c || b + c <= a || c + a <= b) throw a;//当不符合三角形条件抛出异常信息
    	return sqrt(s * (s - a) * (s - b) * (s - c));
    }

书上例题14.2

#include <iostream>
    using namespace std;
    
    
    int main()
    {
    	void f1();
    	try
    	{
    		f1();
    	}
    	catch (double)
    	{
    		cout << "OK!" << endl;
    	}
    	cout << "end0" << endl;
    	system("pause");
    	return 0;
    }
    
    void f1()
    {
    	void f2();
    	try
    	{
    		f2();
    	}
    	catch (char)
    	{
    		cout << "OK1" << endl;
    	}
    	cout << "endl" << endl;
    }
    
    void f2()
    {
    	void f3();
    	try
    	{
    		f3();
    	}
    	catch (int)
    	{
    		cout << "OK2" << endl;
    	}
    	cout << "end2" << endl;
    }
    
    void f3()
    {
    	double a = 0;
    	try
    	{
    		throw a;
    	}
    	catch (float)
    	{
    		cout << "OK3" << endl;
    	}
    	cout << "end3" << endl;
    }