RWTValHashMapIterator<K,T,H,EQ,A>

Module:  Essential Tools Module   Group:  STL Extension-based Collection Classes

Does not inherit

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Members

container() key()

operator()() operator++()

reset() RWTValHashMapIterator<K,T,H,EQ,A>()

value()

#include<rw/tvhdict.h>
RWTValHashMap<K,T,H,EQ,A> m;
RWTValHashMap<K,T,H,EQ,A> itr(m);

RWTValHashMapIterator iprovides the traditional Tools.h++ iterator interface to the standard library-based collections. (An STL iterator interface is provided through RWTValHashMap::iterator.)

Iteration over an RWTValHashMap is pseudorandom and dependent on the capacity of the underlying hash table and the hash function being used. The only usable 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.

The value type T must have operator== defined.

None

#include <functional>
#include <rw/tvhdict.h>
#include <iostream>
#include <rw/cstring.h>

int main() {
   RWTValHashMap
     <RWCString, int, RWTHasher<RWCString>, std::equal_to<RWCString> >
       age(RWCString::hash);
   RWTValHashMapIterator
     <RWCString, int, RWTHasher<RWCString>, std::equal_to<RWCString> >
       itr(age);

   age.insert(RWCString("John"), 30);
   age.insert(RWCString("Steve"),17);
   age.insert(RWCString("Mark"),24);

   while(itr()) {
     std::cout << itr.key() 
               << "\'s age is " 
               << itr.value() 
               << std::endl;
   }

   return 0;
}

Program Output (not necessarily in this order):

John's age is 30
Steve's age is 17
Mark's age is 24

RWTValHashMapIterator<K,T,H,EQ,A>(RWTValHashMap<K,T,H,EQ,A>& 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.

bool
operator()();

Advances self to the next element. Returns false if the iterator has advanced past the last item in the container and true otherwise.

bool
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.

RWTValHashMap<K,T,H,EQ,A>*
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.

void
reset();
void
reset(RWTValHashMap<K,T,H,EQ,A>& 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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