Listing 1

struct InputObj {};

class ProcessorMgr
{
private:
  typedef void (*processingFunction) (InputObj);
  std::map<std::string, processingFunction> my_processors;
public:
  void addProcessor(std::string input_category, processingFunction func) 
  { my_processors[input_category] = func; }

  void processInput(std::string input_category, InputObj i)
  { (my_processors.find(input_category)->second)(i); }
}; 
void processFoo(InputObj i) {  /* ... */ }
void processBar(InputObj i) {  /* ... */ }

int main()
{
  ProcessorMgr mgr;
  mgr.addProcessor("foo", processFoo);
  mgr.addProcessor("bar", processBar);
  InputObj x1, x2;
  mgr.processInput("foo", x1);
  mgr.processInput("bar", x2);

  return 0;
}