Having some issues with function/const

[gsoble]

Okay, so for an assignment I need to write a function called find() that returns a reference to a vector. So I have vector <int> & find(string & key); If I do this, I get the obvious warning warning: reference to local variable 'lineNum' returned [enabled by default].

If I do vector<int> & find(string & key) const; I get a huge error that starts out like

In member function 'std::vector<int>& index_table::find(std::string&) const':
indextable.cpp:74:30: error: no match for 'operator='

Am I using the const identifier incorrectly? If not, is there anything else that I should change to alleviate this headache?

[liuyang]

So from the warning, I guess your code looks like:

vector<int>& find(string &key)
{
    vector<int> lineNum;
    // other things
    return lineNum;
}

You shouldn't return a reference to a local variable. I don't why you have to return a reference to a vector. To my understanding, you could declare the function like this:

vector<int> find(const string &key)

or this

vector<int>& find(vector<int> &lineNum, const string &key)
{
    // operate on passed lineNum directly
    return lineNum;
}

[gsoble]

For the assignment it requires us to return a reference to a vector (for some reason).

[liuyang]

Did your assignment provide the function prototype? Maybe you can try my 2nd option.

[gsoble]

That seemed to make it work. The assignment said to function should take a string reference, but didn't specify anything else. That's the only way I can seem to get it though.

[MiiNiPaa]

Can you post exact wording of your assigment?