RWTValHashMultiMap(3C++) RWTValHashMultiMap(3C++)
Name
RWTValHashMultiMap<K,T,H,EQ> - Rogue Wave library class
Synopsis
#include <rw/tvhmmap.h>
RWTValHashMultiMap<K,T,H,EQ> m;
Standard C++ Library Dependent!RWTValHashMultiMap requires the Standard C++ Library.
Description
This class maintains a collection of keys, each with an associated item
of type T. These pairs are stored according to a hash object of type H.
H must provide a hash function on elements of type K via a public member
unsigned long operator()(const K& x) const Equivalent keys within the
collection will be grouped together based on an equality object of type
EQ. EQ must ensure this grouping via public member
bool operator()(const K& x, const K& y) const which should return true
if x and y are equivalent. RWTValHashMultiMap<K,T,H,EQ> may contain
multiple keys that compare equal to each other. (RWTValHashMap<K,T,H,EQ>
will not accept a key that compares equal to any key already in the
collection.) Equality is based on the comparison object and not on the
== operator.
Persistence
Isomorphic.
Examples
//
// tvhmmrat.cpp
//
#include<rw/tvhmmap.h>
#include<iostream.h>
#include<rw/cstring.h>
struct silly_hash{
unsigned long operator()(RWCString x) const
{ return x.length() * (long)x[0]; }
};
int main(){
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RWCString trd = "Third";
RWTValHashMultiMap<RWCString,int,silly_hash,equal_to<RWCString> >
contest;
contest.insert("First", 7);
contest.insert(trd,3);
contest.insert(trd,6); // self contains two distinct values
//equivalent to trd
contest.insert("Second",2);
contest.resize(8);
cout << "The table is " << contest.fillRatio() * 100.0
<< "% full<< endl;
return 0;
}
Program Output:
Related Classes
The table is 50% full
Class RWTValHashMap<K,T,H,EQ> offers the same interface to a collection
that will not accept multiple keys that compare equal to each other.
Class rw_hashmultimap<K,T,H,EQ> is the C++-standard collection that
serves as the underlying implementation for this collection.
Public Typedefs
typedef rw_hashmultimap<K,T,H,EQ> container_type;
typedef container_type::iterator iterator;
typedef container_type::const_iterator const_iterator;
typedef container_type::size_type size_type;
typedef pair <const K,T> value_type;
typedef pair <const K,T>& reference;
typedef const pair<const K,T>& const_reference;
Public Constructors
RWTValHashMultiMap<K,T,H,EQ>();
Constructs an empty map.
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RWTValHashMultiMap(3C++) RWTValHashMultiMap(3C++)
RWTValHashMultiMap<K,T,H,EQ>
(const rw_hashmultimap<K,T,H,EQ>& m);
Constructs a map by copying all elements of m.
RWTValHashMultiMap<K,T,H,EQ>
(const RWTValHashMultiMap<K,T,H,EQ>& rwm);
Copy constructor.
RWTValHashMultiMap<K,T,H,EQ>
(const value_type* first, const value_type* last);
Constructs a map by copying elements from the array of association pairs
pointed to by first, up to, but not including, the association pointed to
by last.
Public Member Operators
RWTValHashMultiMap<K,T,H,EQ>&
operator=(const RWTValHashMultiMap<K,T,H,EQ>& m);
RWTValHashMultiMap<K,T,H,EQ>&
operator=(const rw_hashmultimap<K,T,H,EQ>& m);
Destroys all elements of self and replaces them by copying all
associations from m.
bool
operator==(const RWTValHashMultiMap<K,T,H,EQ>& m) const;
bool
operator==(const rw_hashmultimap<K,T,H,EQ>& m) const;
Returns true if self compares equal to m, otherwise returns false. Two
collections are equal if both have the same number of entries, and
iterating through both collections produces, in turn, individual keys
that compare equal to each other.
Public Member Functions
void
apply(void (*fn)(const K&, T&, void*),void* d);
void
apply(void (*fn)(const K&,const T&, void*), void* d) const;
Applies the user-defined function pointed to by fn to every association
in the collection. This function must have one of the prototypes:
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void yourfun(const K&, T& a, void* d);
void yourfun(const K&, const T& a,void* d);
Client data may be passed through parameter d.
void
applyToKeyAndValue(void (*fn)(const K&, T&, void*),void* d);
void
applyToKeyAndValue
(void (*fn)(const K&,const T&,void*), void* d) const;
This is a deprecated version of the apply member above. It behaves
exactly the same as apply.
iterator
begin();
const_iterator
begin() const;
Returns an iterator positioned at the first pair in self.
size_type
capacity() const;
Returns the number of buckets(slots) available in the underlying hash
representation. See resize below.
void
clear();
Clears the collection by removing all items from self. Each key and its
associated item will have its destructor called.
bool
contains(const K& key) const;
Returns true if there exists a key j in self that compares equal to key,
otherwise returns false.
bool
contains
(bool (*fn)(const_reference,void*), void* d) const;
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Returns true if there exists an association a in self such that the
expression ((*fn)(a,d)) is true, otherwise returns false. fn points to a
user-defined tester function which must have prototype:
bool yourTester(const_reference a, void* d);
Client data may be passed through parameter d.
iterator
end();
const_iterator
end() const;
Returns an iterator positioned "just past" the last association in self.
size_type
entries() const;
Returns the number of associations in self.
float
fillRatio() const;
Returns the ratio entries()/capacity().
bool
find(const K& key, Key& r) const;
If there exists a key j in self that compares equal to key, assigns j to
r and returns true. Otherwise, returns false and leaves the value of r
unchanged.
bool
find (bool (*fn)(const_reference,void*),
void* d,pair<K,T>& r) const;
If there exists an association a in self such that the expression
((*fn)(a,d)) is true, assigns a to r and returns true. Otherwise,
returns false and leaves the value of k unchanged. fn points to a user-
defined tester function which must have prototype:
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RWTValHashMultiMap(3C++) RWTValHashMultiMap(3C++)
bool yourTester(const_reference a, void* d);
Client data may be passed through parameter d.
bool
findValue(const K& key, T& r) const;
If there exists a key j in self that compares equal to key, assigns the
item associated with j to r and returns true. Otherwise, returns false
and leaves the value of r unchanged.
bool
findKeyValue(const K& key, K& kr, T& tr) const;
If there exists a key j in self that compares equal to key, assigns j to
kr, assigns the item associated with j to tr, and returns true.
Otherwise, returns false and leaves the values of kr and tr unchanged.
bool
insert(const K& key, const T& a);
Adds key with associated item a to the collection. Returns true.
bool
insertKeyAndValue(const K& key, const T& a);
This is a deprecated version of the insert member above. It behaves
exactly the same as insert.
bool
isEmpty() const;
Returns true if there are no items in the collection, false otherwise.
size_type
occurrencesOf(const K& key) const;
Returns the number of keys j in self that compares equal to key.
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size_type
occurrencesOf
(bool (*fn)(const_reference,void*),void* d) const;
Returns the number of associations a in self such that the
expression((*fn)(a,d)) is true. fn points to a user-defined tester
function which must have prototype:
bool yourTester(const_reference a, void* d);
Client data may be passed through parameter d.
bool
remove(const K& key);
Removes the first association with key j in self such that j compares
equal to key and returns true. Returns false if there is no such
association.
bool
remove(bool (*fn)(const_reference,void*), void* d);
Removes the first association a in self such that the expression
((*fn)(a,d)) is true and returns true. Returns false if there is no such
element. fn points to a user-defined tester function which must have
prototype:
bool yourTester(const_reference a, void* d);
Client data may be passed through parameter d.
size_type
removeAll(const K& key);
Removes all associations with key j in self where j compares equal to
key. Returns the number of items removed.
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size_type
removeAll(bool (*fn)(const_reference,void*), void* d);
Removes all associations a in self such that the expression
((*fn)(a,d))is true. Returns the number of items removed. fn points to
a user-defined tester function which must have prototype:
bool yourTester(const_reference a, void* d);
Client data may be passed through parameter d.
void
resize(size_type sz);
Changes the capacity of self by creating a new hashed multimap with a
capacity of sz . resize then copies every element of self into the new
container and finally swaps the internal representation of the new
container with self.
rw_hashmultimap<K,T,H,EQ>&
std();
const rw_hashmultimap<K,T,H,EQ>&
std() const;
Returns a reference to the underlying C++-standard collection that serves
as the implementation for self. This reference may be used freely,
providing accessibility to the C++-standard interface and
interoperability with other software components that make use of the
C++-standard collections.
Related Global Operators
RWvostream&
operator<<(RWvostream& strm,
const RWTValHashMultiMap<K,T,H,EQ>& coll);
RWFile&
operator<<(RWFile& strm,
const RWTValHashMultiMap<K,T,H,EQ>& coll);
Saves the collection coll onto the output stream strm, or a reference to
it if it has already been saved.
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RWvistream&
operator>>(RWvistream& strm,
RWTValHashMultiMap<K,T,H,EQ>& coll);
RWFile&
operator>>(RWFile& strm, RWTValHashMultiMap<K,T,H,EQ>& coll);
Restores the contents of the collection coll from the input stream strm.
RWvistream&
operator>>(RWvistream& strm, RWTValHashMultiMap<K,T,H,EQ>*& p);
RWFile&
operator>>(RWFile& strm, RWTValHashMultiMap<K,T,H,EQ>*& p);
Looks at the next object on the input stream strm and either creates a
new collection off the heap and sets p to point to it, or sets p to point
to a previously read instance. If a collection is created off the heap,
then you are responsible for deleting it.
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