Re: map<string, vector<string> > Question about partial initialization

From:

"Mr. K.V.B.L." <kenverybigliar@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Thu, 11 Sep 2008 12:09:58 -0700 (PDT)

Message-ID:

<96ec9f6a-a5fe-47b4-ad49-cad355401282@c65g2000hsa.googlegroups.com>

On Sep 11, 1:25 pm, "Mr. K.V.B.L." <kenverybigl...@gmail.com> wrote:

I want to start a map with keys but an empty vector<string>. Not sure
what the syntax is here.

Something like:

    map<string, vector<string> > MapVector;

    MapVector.insert(make_pair("string1", new vector<string>));
    MapVector.insert(make_pair("string2", new vector<string>));
    MapVector.insert(make_pair("string3", new vector<string>));
    MapVector.insert(make_pair("string4", new vector<string>));
    MapVector.insert(make_pair("string5", new vector<string>));
    MapVector.insert(make_pair("string6", new vector<string>));

Obviously this isn't right, hence my question.

Eventually I pieced together the following:

#include <cstdio>
#include <iostream>
#include <string>
#include <map>
#include <vector>

using namespace std;

typedef map<string, vector<string> > MapVector;

int main(int argc, char *argv[])
{
    vector<string> stringVector;
    MapVector mp;

    mp.insert(make_pair("string1", stringVector));
    mp.insert(make_pair("string2", stringVector));
    mp.insert(make_pair("string3", stringVector));
    mp.insert(make_pair("string4", stringVector));
    mp.insert(make_pair("string5", stringVector));
    mp.insert(make_pair("string6", stringVector));

    MapVector::iterator iter = mp.find("string5");
    if (iter != mp.end()) {
        iter->second.push_back("substring1");
        iter->second.push_back("substring2");
        iter->second.push_back("substring3");
        iter->second.push_back("substring4");
        iter->second.push_back("substring5");
        iter->second.push_back("substring6");
        iter->second.push_back("substring7");
    }

    for (MapVector::const_iterator Walker = mp.begin(); Walker !=
mp.end(); ++Walker) {
        cout << Walker->first << endl;
        for (vector<string>::const_iterator WalkerVector = Walker-

second.begin();

            WalkerVector != Walker->second.end(); ++WalkerVector)
        {
            cout << *WalkerVector << endl;
        }
    }
}

This seems to work. What I was concerned over was dumping
'stringVector' into each new call to insert(). I was hoping it
wouldn't be a reference but a new object copy. The program gives this
output:

string1
string2
string3
string4
string5
substring1
substring2
substring3
substring4
substring5
substring6
substring7
string6

If you have any further thoughts, please feel free. My thanks.

Kelly