TITLE: Amusing infinite loop bug


PROBLEM: dls@gwd.dsto.gov.au (David Silver), 16 Sep 93

[ Can you spot the infinite recursion in the following program (without
  looking ahead at the answer? -adc ]

One of the guys in our project team experienced a little finger trouble
and managed to come up with this.  When run, the program never terminates.
 
class Base {
public:
  Base() {}
  virtual void func() { /* do something */ }
};

class Derived : public Base {
public:
  Derived() {}
  virtual void func()
  {
    Base:func();
    /* do something else */
  }
};

main()
{
  Derived d;
  d.func();    // Never returns!
}


RESPONSE: grumpy@cbnewse.cb.att.com (Paul J Lucas)

Of course, the quality of the implementation will dictate whether
the user is warned about the unused label Base.

Base: in that context is a label.  Just as in C, labels are
in a unique scope, hence there is no problem with having
Base as a class and Base as a label.