Map problem

[tech]

Hi, I want to create a map of named events from a const array.

eg std::map<std::s tring, HANDLEthis needs to be intialised so that

initially it will be contain the names of the all the events with a
NULL handle then
i can do the following

std::map<std::s tring, HANDLEEvents;
std::map<std::s tring, HANDLE>::iterat or it;

const std::string[] { "EventName1 ", "EventName2 ", "EventName3 "};

it = Events.begin();

while (it != Events.end())
{
Events[it->first] = CreateEvent(NUL L,FALSE,FALSE, it->first.c_str( ))
++it;
}


So i f i ever need a new event all i need to do is add it to the array
and the event will be created
managed, destroyed just using the map.

However do i use the string array to initalise the map keys however?

[Jim Langston]

Re: Map problem

tech wrote:

Hi, I want to create a map of named events from a const array.
>
eg std::map<std::s tring, HANDLEthis needs to be intialised so that
>
initially it will be contain the names of the all the events with a
NULL handle then
i can do the following
>
std::map<std::s tring, HANDLEEvents;
std::map<std::s tring, HANDLE>::iterat or it;
>
const std::string[] { "EventName1 ", "EventName2 ", "EventName3 "};

I think you meant to give this a name. Something Like:
const std::string EventNames[] { "EventName1 ", "EventName2 ", "EventName3 "};

it = Events.begin();
>
while (it != Events.end())
{
Events[it->first] = CreateEvent(NUL L,FALSE,FALSE, it->first.c_str( ))
++it;
}
>
>
So i f i ever need a new event all i need to do is add it to the array
and the event will be created
managed, destroyed just using the map.
>
However do i use the string array to initalise the map keys however?

Simplest would be something like:

for ( int i = 0; i < sizeof( EventNames ) / sizeof( EvenNames[0] ); ++i )
Events[EventNames[i]] = NULL;

the sizeof( Eventnames ) / sizeof( EventNames[0]] may be a little off. Thsi
just is to determine how many names are in the array.

But really, for a constant array of text I'd just go with a char*[]

const char* EventNames[] = { "EventName1 ", "EventName2 ", "EventName3 "};

Notice that this isn't using C style char arrays, but an array of character
pointers.



--
Jim Langston
tazmaster@rocke tmail.com

[Michael.Boehnisch@gmail.com]

Re: Map problem

On 11 Apr., 12:48, "Jim Langston" <tazmas...@rock etmail.comwrote :

tech wrote:

Hi, I want to create a map of named events from a const array.

>

However do i use the string array to initalise the map keys however?

>
Simplest would be something like:
>
for ( int i = 0; i < sizeof( EventNames ) / sizeof( EvenNames[0] ); ++i )
Events[EventNames[i]] = NULL;
>

Alternatively, you may change the EventNames[] array to
std::pair<std:: string, HANDLE>:

typedef std::pair<std:: string, HANDLEPair;

Pair EventNames[] = {
Pair( "EventName1 ", 0 ),
Pair( "EventName2 ", 0 ),
...
};

This looks more ugly at first (the typedef enhances usability a
little). However, you now can do the initialization like this:

std::map<std::s tring, HANDLEEvents(
&EventNames[0],
&EventNames[ sizeof EventNames / sizeof( Pair ) ]
);


This avoids explicit loops and can be used in a constructor
initializer list. Its a mere matter of taste.

best,

Michael