RWTPtrHashMapIterator(3C++) RWTPtrHashMapIterator(3C++)
Name
RWTPtrHashMapIterator<K,T,H,EQ> - Rogue Wave library class
Synopsis
#include<rw/tphdict.h>
RWTPtrHashMap<K,T,H,EQ> m;
RWTPtrHashMap<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 RWTPtrHashDictionaryIterator described
in Appendix A.
DescriptionRWTPtrHashMapIterator is supplied with Tools.h++ 7.x to provide an
iterator interface to the Standard Library based collections that has
backward compatibility with the container iterators provided in Tools.h++
6.x. Iteration over an RWTPtrHashMap is pseudorandom and dependent on the
capacity of the underlying hash table and the hash function being used.
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 operator(). For both
operator++ and operator(), iterating past the last element will return a
value equivalent to boolean false. Once this state is reached, continued
increments will return a value equivalent to false until reset() is
called.
Persistence
None
Examples
#include<rw/tphdict.h>
#include<iostream.h>
#include<rw/cstring.h>
struct silly_h{
unsigned long operator()(RWCString x) const
{ return x.length() * (long)x(0); }
};
int main(){
RWTPtrHashMap
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RWTPtrHashMapIterator(3C++) RWTPtrHashMapIterator(3C++)
<RWCString,int,silly_h,equal_to<RWCString> > age;
RWTPtrHashMapIterator
<RWCString,int,silly_h,equal_to<RWCString> > itr(age);
age.insert(new RWCString("John"),new int(30));
age.insert(new RWCString("Steve"),new int(17));
age.insert(new RWCString("Mark"),new int(24));
//Duplicate insertion is rejected
age.insert(new RWCString("Steve"),new int(24));
for(;++itr;)
cout << *itr.key() << "'s age is " << *itr.value() << endl;
return 0;
}
Program Output (not necessarily in this order)
John's age is 30
Mark's age is 24
Public Constructors
Steve's age is 17
RWTPtrHashMapIterator<K,T,H,EQ>(RWTPtrHashMap<K,T,H,EQ>&h);
Creates an iterator for the hashed map h. The iterator begins in an
undefined state and must be advanced before the first element will be
accessible.
Public Member Operators
K*
operator()();
Advances self to the next element, dereferences the resulting iterator
and returns its key. If the iterator has advanced past the last item in
the container, the element returned will be a nil pointer equivalent to
boolean false.
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 multi-map, self
will now reference an undefined value and a value equivalent to false
will be returned. Otherwise, a value equivalent to true is returned.
Note: no post-increment operator is provided.
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RWTPtrHashMapIterator(3C++) RWTPtrHashMapIterator(3C++)
Public Member Functions
RWTPtrHashMap<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 referenced by self.
Undefined if self is not referencing a value within the map.
void
reset();
void
reset(RWTPtrHashMap<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 hashed map with
reset() will reset the iterator on that container.
T*
value();
Returns the value portion of the association pointed to by self. The
behavior is undefined if the map is empty.
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