LinuxQuestions.org - [SOLVED] template problem in c++

The problem is that the compiler can't know that
list<pair<K, V> >::iterator
is the name of a type. Even though the compiler has at that point seen the whole definition of list so you would expect it to know iterator is a name of a type inside list, the C++ standard has rules that prevent it from knowing.

In this situation, I strongly prefer to use several typedefs to break up the ugly declarations. So you could fix your problem just by adding the keyword typename to your declaration. But I personally think it is very ugly to use typename that way anywhere other than right after the keyword typedef

I haven't tested any of this, but I think it is right:

Code:

#include<list>

#include<utility>

#include<algorithm>

#include<string>

#include<vector>

using namespace std;



template<class K, class V> struct Hash{

        typedef list<pair<K, V> > my_list;

        typedef typename my_list::iterator iterator;

        my_list *hash;        

        int (*hashFunction)(K key);        

        int buckets;                        



        Hash(int (*hashFunction)(K), int buckets){};



        ~Hash(){};



        iterator put(K key, V value, int pos_flag = -1){ return 0; };

};

Actually I prefer the following, but that makes changes further from the scope of your question

Code:

#include<list>

#include<utility>

#include<algorithm>

#include<string>

#include<vector>



template<class K, class V> struct Hash{

        typedef std::pair<K, V> pair;

        typedef std::list<pair> list;

        typedef typename list::iterator iterator;

        list *hash;        

        int (*hashFunction)(K key);        

        int buckets;                        



        Hash(int (*hashFunction)(K), int buckets){};



        ~Hash(){};



        iterator put(K key, V value, int pos_flag = -1){ return 0; };

};