Tools.h++ Manual

18-10 104011 Tandem Computers Incorporated

Here’s a slightly more complicated example:

template <class T> void List::insert(T* obj)

{

RWPRECONDITION( obj!= 0 );

head = new Link(head, obj);

RWPOSTCONDITION( this->contains(obj) );

}

The job of this function is to insert the object pointed to by the argument into a

linked list of pointers to objects of type T. The only precondition for the

function to work is that the pointer "

obj"

not be nil. If this condition is

satisﬁed, then the function guarantees to successfully insert the object. This is

checked by the postcondition clause.

The macros

RWPRECONDITION

and

RWPOSTCONDITION

are deﬁned in

and compile out to no-ops unless the preprocessor macro

RWDEBUG

has been defined:

#ifdef RWDEBUG

# define RWPRECONDITION(a)assert(a)

# define RWPOSTCONDITION(a)assert(a)

#else

# define RWPRECONDITION(a)((void*)0)

# define RWPOSTCONDITION(a)((void*)0)

#endif