Errors when trying to print out vector of list of objects?

Question

So I'm trying ti print out a vector of list of objects I have in a hash table with the following code but I keep getting these errors and I'm not sure why...

SeparateChaining.h: In member function 'void HashTable<HashedObj>::print()':
SeparateChaining.h:165:13: error: need 'typename' before 'std::list<HashedObj>::iterator' because 'std::list<HashedObj>' is a dependent scope
SeparateChaining.h:165:39: error: expected ';' before 'li'
SeparateChaining.h:166:17: error: 'li' was not declared in this scope
SeparateChaining.h: In instantiation of 'void HashTable<HashedObj>::print() [with HashedObj = Symbol]':
Driver.cpp:72:21:   required from here
SeparateChaining.h:165:13: error: dependent-name 'std::list<HashedObj>::iterator' is parsed as a non-type, but instantiation yields a type
SeparateChaining.h:165:13: note: say 'typename std::list<HashedObj>::iterator' if a type is meant

Here is the snippet of my class featuring the print function:

class HashTable
{

    /// ....



        void print()
        {

            for(int i = 0; i < theLists.size(); ++i)
            {
                list<HashedObj>::iterator li;
                for(li = theLists[i].begin(); li != theLists[i].end(); ++li)
                    cout << "PLEASE WORK" << endl;
            }
    /*
            for(auto iterator = oldLists.begin(); iterator!=oldLists.end(); ++iterator) 
                for(auto itr = theLists.begin(); itr!=theLists.end(); ++itr)
                    cout << *itr << endl;
    */
        }

      private: 
         vector<list<HashedObj>> theLists;   // The array of Lists

};

And here's how I overload the ostream operator<< (in the Symbol Class):

friend ostream & operator <<(ostream & outstream, Symbol & symbol) //overloaded to print out the the HashTable
{
    int num = symbol.type;
    string name = symbol.data;
    outstream << name << " : " << num << "\n";
    return outstream;
}

Can you show the whole class? Or could you first add typename before list::iterator as the compiler said? — Shane Lu, Mar 19 '14 at 05:13

score 0 · Accepted Answer · edited May 23 '17 at 10:26

0

If you read the error carefully, it is saying that this line:

list<HashedObj>::iterator li;

Should read as:

typename list<HashedObj>::iterator li;

Basically, the you need to tell the compiler that you are dealing with a type. See this question or this question for more details on what is going on.

You might have other errors, but you need to resolve these first.

edited May 23 '17 at 10:26

Community

1
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answered Mar 19 '14 at 05:28

Nathan S.

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score 0 · Answer 2 · edited May 23 '17 at 10:26

SeparateChaining.h:165:13: error: need 'typename' before 'std::list<HashedObj>::iterator' because 'std::list<HashedObj>' is a dependent scope

The compiler cannot determine if list<HashedObj> is a static field or a type, so it assumes that list<HashedObj> is a field causing these syntax errors. You have to place a typename in front of the declaration to convince the compiler otherwise. It should look like:

typename list<HashedObj>::iterator li;

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Errors when trying to print out vector of list of objects?

2 Answers2