catchref.cpp

Think in C++ 第二版源码

//: C23:Catchref.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// Why catch by reference?
#include <iostream>
using namespace std;

class Base {
public:
  virtual void what() {
    cout << "Base" << endl;
  }
};

class Derived : public Base {
public:
  void what() {
    cout << "Derived" << endl;
  }
};

void f() { throw Derived(); }

int main() {
  try {
    f();
  } catch(Base b) {
    b.what();
  }
  try {
    f();
  } catch(Base& b) {
    b.what();
  }
} ///:~