RWTValHashMapIterator(3C++) RWTValHashMapIterator(3C++)
Name
RWTValHashMapIterator<K,T,H,EQ> - Rogue Wave library class
Synopsis
#include<rw/tvhdict.h>
RWTValHashMap<K,T,H,EQ> m;
RWTValHashMap<K,T,H,EQ> itr(m);
Please Note!
If you have the Standard C++ Library, use the interface described here.
Otherwise, use the interface for RWTValHashDictionaryIterator described
in Appendix A.
DescriptionRWTValHashMapIterator is supplied with Tools 7 to provide an iterator
interface to RWTValHashMapIterator that has backward compatibility with
the container iterators provided in Tools 6. Iteration over an
RWTValHashMap is pseudorandom and dependent on the capacity of the
underlying hash table and the hash function being used. The only useable
relationship between consecutive elements is that elements which are
defined to be equivalent by the equivalence object, EQ, will remain
adjacent. The current item referenced by this iterator is undefined
after construction or after a call to reset(). The iterator becomes
valid after being advanced with either a preincrement or an operator().
For both operator++ and operator(), iterating past the last element will
return a value equivalent to boolean false. Continued increments will
return a value equivalent to false until reset() is called.
Persistence
None
Example
#include<rw/tvhdict.h>
#include<iostream.h>
#include<rw/cstring.h>
struct silly_h{
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RWTValHashMapIterator(3C++) RWTValHashMapIterator(3C++)
unsigned long operator()(const RWCString& x) const
{ return x.length() * (long)x(0); }
};
int main(){
RWTValHashMap
<RWCString,int,silly_h,equal_to<RWCString> > age;
RWTValHashMapIterator
<RWCString, int, silly_h, equal_to<RWCString > > itr(age);
age.insert(RWCString("John"), 30);
age.insert(RWCString("Steve"),17);
age.insert(RWCString("Mark"),24);
//Duplicate insertion rejected
age.insert(RWCString("Steve"),24);
for(;itr();)
cout << itr.key() << "'s age is " << itr.value() << endl;
return 0;
}
Program Output (not necessarily in this order)
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RWTValHashMapIterator(3C++) RWTValHashMapIterator(3C++)
John's age is 30
Steve's age is 17
Mark's age is 24
Public Constructors
RWTValHashMapIterator<K,T,H,EQ>
(RWTValHashMap<K,T,H,EQ>&h);
Creates an iterator for the hashmap h. The iterator begins in an
undefined state and must be advanced before the first element will be
accessible.
Public Member Operators
RWBoolean
operator()();
Advances self to the next element. Returns false if the iterator has
advanced past the last item in the container and true otherwise.
RWBoolean
operator++();
Advances self to the next element. If the iterator has been reset or
just created self will now reference the first element. If, before
iteration, self referenced the last association in the multimap, self
will now reference an undefined value and false will be returned.
Otherwise, true is returned. Note: no postincrement operator is provided.
Public Member Functions
RWTValHashMap<K,T,H,EQ>*
container() const;
Returns a pointer to the collection being iterated over.
K
key() const;
Returns the key portion of the association currently pointed to by self.
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RWTValHashMapIterator(3C++) RWTValHashMapIterator(3C++)
void
reset();
void
reset(RWTValHashMap<K,T,H,EQ>& h);
Resets the iterator so that after being advanced it will reference the
first element of the collection. Using reset() with no argument will
reset the iterator on the current container. Supplying a RWTValHashMap
to reset() will reset the iterator on that container.
T
value();
Returns the value portion of the association referenced by self.
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