demo_exception_handling_2.cpp

对于一个初涉VC＋＋的人来书

//**********************************************************
//catch说明的捕获异常的类型必须和throw引发异常的类型相匹配,
//若类型都不匹配,可以使用缺省的异常捕获和处理: catch(...)
//注意: catch捕获块的顺序很重要,因为顺序匹配执行.
//**********************************************************

# include <iostream.h>

void trigger(int code)
{
	try
	{
		if(code==0) throw code;   //引发int类型的异常
		if(code==1) throw 100;    //引发int类型的异常
		if(code==2) throw 100L;   //引发long int类型的异常
		if(code==3) throw 'x';    //引发char类型的异常
		if(code==4) throw "x";    //引发char *类型的异常
		if(code==5) throw 3.14f;  //引发float类型的异常
		if(code==6) throw 3.14;   //引发double类型的异常
	}

	//若放到前面,则编译器会给出6个错误警告
	//指出后面的所有6个catch块都不起作用了!
//	catch(...) 
//	{
//		cout<<"Catching default ..."<<endl;
//	}

	//throw-catch不但可以传递异常值,也可以传递异常值
	catch(long int i)
	{
		cout<<"Catching integer : "<<i<<endl;
	}
	catch(char ch)
	{
		cout<<"Catching char : "<<ch<<endl;
	}
	catch(char *ch)
	{
		cout<<"Catching char * : "<<ch<<endl;
	}
	catch(float f)
	{
		cout<<"Catching float : "<<f<<endl;
	}
	catch(double d)
	{
		cout<<"Catching double : "<<d<<endl;
	}

	catch(...) //一般放在最后
	{
		cout<<"Catching default ..."<<endl;
	}

	return;
}

int main()
{
	cout<<"Execute Function: trigger(0)"<<endl;
	trigger(0);
	cout<<endl;
	cout<<"Execute Function: trigger(1)"<<endl;
	trigger(1); 
	cout<<endl;
	cout<<"Execute Function: trigger(2)"<<endl;
	trigger(2);
	cout<<endl;
	cout<<"Execute Function: trigger(3)"<<endl;
	trigger(3); 
	cout<<endl;
	cout<<"Execute Function: trigger(4)"<<endl;
	trigger(4);
	cout<<endl;
	cout<<"Execute Function: trigger(5)"<<endl;
	trigger(5);
	cout<<endl;
	cout<<"Execute Function: trigger(6)"<<endl;
	trigger(6);
	cout<<endl;

	return 0;
}

/*
Execute Function: trigger(0)
Catching default ...

Execute Function: trigger(1)
Catching default ...

Execute Function: trigger(2)
Catching integer : 100

Execute Function: trigger(3)
Catching char : x

Execute Function: trigger(4)
Catching char * : x

Execute Function: trigger(5)
Catching float : 3.14

Execute Function: trigger(6)
Catching double : 3.14

Press any key to continue
*/