using a std::bitset in an iterator

[Sean Farrow]

Hi:
I have an iterator defined as follows:
std::map<std::bitset<6>, int>::iterator DotsIterator, SignsIterator;

I get errors that std::bitset does not declare the < operator. Does this
mean I can not use std::bitset in an iterator. Any help apreciated.

Cheers

Sean.

[Juha Nieminen]

Sean Farrow wrote:

Hi:
I have an iterator defined as follows:
std::map<std::bitset<6>, int>::iterator DotsIterator, SignsIterator;

I get errors that std::bitset does not declare the < operator. Does this
mean I can not use std::bitset in an iterator. Any help apreciated.

You have to specify a comparison operator for the map to use. For
example like this:

typedef std::bitset<6KeyType;

struct BitSetComp
{
bool operator()(const KeyType& lhs, const KeyType& rhs)
{
return lhs.to_ulong() < rhs.to_ulong();
}
};

int main()
{
typedef std::map<KeyType, int, BitSetCompBitSetMap;
BitSetMap m;
BitSetMap::iterator iter = m.begin();
}

[Pete Becker]

On 2008-08-24 18:38:52 -0400, "Sean Farrow"
<se*********@seanfarrow.co.uksaid:

I have an iterator defined as follows:
std::map<std::bitset<6>, int>::iterator DotsIterator, SignsIterator;

I get errors that std::bitset does not declare the < operator. Does this
mean I can not use std::bitset in an iterator. Any help apreciated.

It means you can't use it in a map. Other containers don't require ordering.

--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)

[Triple-DES]

On 25 Aug, 01:04, Juha Nieminen <[e-mail]:

* You have to specify a comparison operator for the map to use. For
example like this:

typedef std::bitset<6KeyType;

struct BitSetComp
{
* * bool operator()(const KeyType& lhs, const KeyType& rhs)
* * {
* * * * return lhs.to_ulong() < rhs.to_ulong();
* * }

};

nit: the operator must be const, otherwise the predicate can't be used
with map

int main()
{
* * typedef std::map<KeyType, int, BitSetCompBitSetMap;
* * BitSetMap m;
* * BitSetMap::iterator iter = m.begin();
}

DP

[Sean Farrow]

Hi:
Thanks to all. I've now solved the issues.
Sean.
"Pete Becker" <pe**@versatilecoding.comwrote in message
news:2008082422581116807-pete@versatilecodingcom...

On 2008-08-24 18:38:52 -0400, "Sean Farrow" <se*********@seanfarrow.co.uk>
said:

>I have an iterator defined as follows:
std::map<std::bitset<6>, int>::iterator DotsIterator, SignsIterator;

I get errors that std::bitset does not declare the < operator. Does this
mean I can not use std::bitset in an iterator. Any help apreciated.

It means you can't use it in a map. Other containers don't require
ordering.

--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)

[Sean Farrow]

Hi:
When executing the following line:
DotsIterator =DotsList.find(dots);

I get the following error:

C2679: binary '=' : no operator found which takes a right-hand operand of
type 'std::_Tree<_Traits>::iterator' (or there . I
is no acceptable conversion)

DotsIterator is defined as:

std::map<std::bitset<6>, int>::iterator DotsIterator;

How can I solve this issue. I'm using visual c++ 2005.

Cheers

Sean.

"Sean Farrow" <se*********@seanfarrow.co.ukwrote in message
news:48***********************@news.zen.co.uk...

Hi:
Thanks to all. I've now solved the issues.
Sean.
"Pete Becker" <pe**@versatilecoding.comwrote in message
news:2008082422581116807-pete@versatilecodingcom...

>On 2008-08-24 18:38:52 -0400, "Sean Farrow"
<se*********@seanfarrow.co.uksaid:

>>I have an iterator defined as follows:
std::map<std::bitset<6>, int>::iterator DotsIterator, SignsIterator;

I get errors that std::bitset does not declare the < operator. Does this
mean I can not use std::bitset in an iterator. Any help apreciated.

It means you can't use it in a map. Other containers don't require
ordering.

--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)