catch基类和子类异常

#include<iostream>
usingnamespacestd;

classX...{
public:
classTrouble...{};
classSmall:publicTrouble...{};
classBig:publicTrouble...{};
voidf()...{throwBig();}
};

intmain()...{
Xx;
try...{
x.f();
}catch(X::Trouble&)...{
cout<<"caughtTrouble"<<endl;
//Hiddenbyprevioushandler:
}catch(X::Small&)...{
cout<<"caughtSmallTrouble"<<endl;
}catch(X::Big&)...{
cout<<"caughtBigTrouble"<<endl;
}catch(...)...{
cout<<"anexceptionwasthrown"<<endl;
}

}/**////:~

结果是catch基类也能捕获子类的异常。

再rethrow一次

#include<iostream>
usingnamespacestd;

classX...{
public:
classTrouble...{};
classSmall:publicTrouble...{};
classBig:publicTrouble...{};
voidf()...{throwBig();}
};

intmain()...{
Xx;

try
...{
try...{
x.f();
}catch(X::Trouble&)...{
cout<<"caughtTrouble"<<endl;
throw;
}catch(X::Small&)...{
cout<<"caughtSmallTrouble"<<endl;
}catch(X::Big&)...{
cout<<"caughtBigTrouble"<<endl;
}


}catch(...)
...{
cout<<"rethrowcaught"<<endl;
}

}/**////:~

可以跑，但是有警告，warning: exception of type `X::Small' will be caught。。。。。。。不晓得原因。