badexception.cpp

C语言数值算法程序大全（第二版）,课本文件

//: C01:BadException.cpp
// From "Thinking in C++, 2nd Edition, Volume 2"
// by Bruce Eckel & Chuck Allison, (c) 2003 MindView, Inc.
// Available at www.BruceEckel.com.
//{-bor}
#include <exception>    // for std::bad_exception
#include <iostream>
#include <cstdio>
using namespace std;

// Exception classes:
class A {};
class B {};

// terminate() handler
void my_thandler() {
  cout << "terminate called\n";
  exit(0);
}

// unexpected() handlers
void my_uhandler1() {
  throw A();
}
void my_uhandler2() {
  throw;
}

// If we embed this throw statement in f or g,
// the compiler detects the violation and reports
// an error, so we put it in its own function.
void t() {
  throw B();
}

void f() throw(A) {
  t();
}
void g() throw(A, bad_exception) {
  t();
}

int main() {
  set_terminate(my_thandler);
  set_unexpected(my_uhandler1);
  try {
    f();
  }
  catch (A&) {
    cout << "caught an A from f\n";
  }
  set_unexpected(my_uhandler2);
  try {
    g();
  }
  catch (bad_exception&) {
    cout << "caught a bad_exception from g\n";
  }
  try {
    f();
  }
  catch (...) {
    cout << "This will never print\n";
  }
} ///:~