Re: Building the name of an executable function

From:
mlimber <mlimber@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Thu, 21 Aug 2008 06:53:17 -0700 (PDT)
Message-ID:
<556a207f-83a9-4d6a-bfa7-879c955a6e4d@a1g2000hsb.googlegroups.com>
On Aug 21, 9:48 am, Miner Jeff <jeff.p.bled...@lmco.com> wrote:

I need to build the name of a function from data in a text file. For
example, after reading the variables 'FCTN_PREFIX' AND 'FCTN_SUFFIX'
from the text file, I need to execute the function:

FCTN_PREFIX & 'TXT1' & FCTN_SUFFIX & 'TXT2';

where TXT1 and TXT2 are hardcoded text; & indicates concatenation.

I assume I could concatenate the text to build the function name and
give it a variable name but how can I then execute that function?


I just posted on this topic on another thread. You might use std::map
to associate your string with a function, something like:

 typedef void (*Fn)();
 typedef std::map<std::string,Fn> MyMap;

 MyMap myMap; // global for the sake of simplicity

 void Hello() {/*...*/}
 void World() {/*...*/}

 void Call( const std::string& str )
 {
   MyMap::const_iterator it = myMap.find( str );
   if( it != myMap.end() )
   {
     it->second();
   }
 }

 int main()
 {
   myMap[ "hello" ] = &Hello;
   myMap[ "world" ] = &World;

   Call( "hello" );
   Call( "world" );
 }

Cheers! --M

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