Advertisement Jump to content
Sign in to follow this  

typeid type_info help please

This topic is 1247 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hi Guys,


Given a set of items all derived from a "BaseItem" class in a container such as

std::vector<BaseItem*> items

I would like to construct a function like this:

bool isTypeInList(Unknown parameter){

 for(auto it=items.begin();it!=items.end();it++)

   if(typeid(*unknown parameter)==typeid(it)

      return true;

return false;


Basically I need to stick a typeid(Torch), typeid(Spear) etc. into the parameter and test if it's in items list.



Share this post

Link to post
Share on other sites
You can pass in a type_info object:
#include <iostream>
#include <typeinfo>
using namespace std;

struct A { virtual ~A() {}; virtual void foobar() {} };
struct B : A { };
struct C : A { };
struct D : A { };

bool contains_type( A** arr, int ct, const type_info& a ) {
    for ( int idx = 0; idx < ct; ++idx ) {
    	if ( a == typeid(*arr[idx]) )
    		return true;
    return false;

int main() {
	B b;
	C c;
	D d;
	const int ct = 2;
	A* arr[ct] = {&b, &c};
	cout << contains_type(arr,ct,typeid(B)) << endl;
	cout << contains_type(arr,ct,typeid(C)) << endl;
	cout << contains_type(arr,ct,typeid(D)) << endl;
	return 0;
Of course, this is a bit of a code smell. Why not have a 'type' attribute as a string within the BaseItem itself and query against that? It'd be less cumbersome as A*, A&, and A are have different type_infos, despite being "the same" in regards to what you're trying to do here. Edited by fastcall22

Share this post

Link to post
Share on other sites
Consider alternatives too:
  • If the type turns out to be important, are you sure you want to lose track of it by storing it in a list of other stuff?
  • Is it possible to covert this from a type query to a virtual function call?

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Advertisement

Important Information

By using, you agree to our community Guidelines, Terms of Use, and Privacy Policy. is your game development community. Create an account for your GameDev Portfolio and participate in the largest developer community in the games industry.

Sign me up!