Initialize const or static map

[shaun]

I should like to use a map as a look-up table from one string to
another. I know the look up I want to use at compile time, and I dont
want to spend time during running to construct the object with a new
map..

Is there any way I can declare a const or static map and fill it such
that this isn't done at run-time (at least, not on each construction of
the object)? There are about 20 entries, not hundreds.

cheers

shaun

[Rolf Magnus]

shaun wrote:

I should like to use a map as a look-up table from one string to
another. I know the look up I want to use at compile time, and I dont
want to spend time during running to construct the object with a new
map..

Is there any way I can declare a const or static map and fill it such
that this isn't done at run-time (at least, not on each construction of
the object)? There are about 20 entries, not hundreds.

No, this isn't possible. You may want to try something like gperf. See
http://www.gnu.org/software/gperf/

[shaun]

In article <dq*************@news.t-online.com>,
Rolf Magnus <ra******@t-online.de> wrote:

Is there any way I can declare a const or static map and fill it such
that this isn't done at run-time (at least, not on each construction of
the object)? There are about 20 entries, not hundreds.

No, this isn't possible. You may want to try something like gperf. See
http://www.gnu.org/software/gperf/

If I have a class with a static map, won't that initialize at run time
but before the main body of the program? Even that would be a bonus.

Is the following possible in a class (this is nearly pseudo code,
derived from a "codecomments.com article):

pair<string, string> a[] = {
pair<string, string>("a","apple"),
pair<string, string>("b","banana"),
}

map<string, string> myMap(a, a + sizeof(a) / sizeof(a[0]) );
where a and myMap are declared static in the header? the strings were
char cont * in the original article, does this make a difference?

[Rolf Magnus]

shaun wrote:

Is there any way I can declare a const or static map and fill it such
that this isn't done at run-time (at least, not on each construction of
the object)? There are about 20 entries, not hundreds.
No, this isn't possible. You may want to try something like gperf. See
http://www.gnu.org/software/gperf/

If I have a class with a static map, won't that initialize at run time
but before the main body of the program?

Yes, that's right.
Even that would be a bonus.

Is the following possible in a class (this is nearly pseudo code,
derived from a "codecomments.com article):

pair<string, string> a[] = {
pair<string, string>("a","apple"),
pair<string, string>("b","banana"),
}

map<string, string> myMap(a, a + sizeof(a) / sizeof(a[0]) );

where a and myMap are declared static in the header?
Yes, that should work.
the strings were char cont * in the original article, does this make a
difference?

Not regarding the correctness, but using std::string will increase the
initialization time, since the strings usually dynamically allocate memory
for the data and copy the contents of the string literals over. They might
even get copied again into the map.
I don't know if that makes a difference for your program. Just wanted to
note it.