"Expression: vector iterator not deferencable" run-time error

Question

The following code inputs words and counts how many times each word appeared in the input. Then the program prints each word and corresponding frequency in the order from lowest to highest.

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

using namespace std;

int main()
{
    string s;
    map<string, int> counters;
    map<int, vector<string> > freq;

    while (cin >> s)
        ++counters[s];

    map<string, int>::const_iterator it = counters.begin();
    for (it; it != counters.end(); ++it)
    {
        freq[it->second].push_back(it->first);
    }

    for (map<int, vector<string> >::const_iterator i = freq.begin();
        i != freq.end(); ++i)
    {
        vector<string>::const_iterator j = i->second.begin();
        cout << i->first << '\t' << *j;
        while (j != i->second.end())
        {
            ++j;
            cout << ", " << *j;
        }
        cout << endl;
    }   

    return 0;
}

The program compiles and runs, but whenever I enter all the words I need and enter EOF the following run-time error appears

Expression: vector iterator not dereferencable

and then the following error also appears

Standard C++ libraries out of range && 0

How to resolve it?

Answer 1

I guess it's because you are dereferencing j when it can point to end:

    cout << i->first << '\t' << *j;
                                ^----- HERE

And here's the change to fix it:

    if (j != i->second.end()) {
        cout << i->first << '\t' << *j;
    }

Answer 2

Got it.

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

using namespace std;

int main()
{
    string s;
    map<string, int> counters;
    map<int, vector<string> > freq;

    while (cin >> s)
        ++counters[s];

    map<string, int>::const_iterator it = counters.begin();
    for (it; it != counters.end(); ++it)
    {
        freq[it->second].push_back(it->first);
    }


    for (map<int, vector<string> >::const_iterator i = freq.begin();
        i != freq.end(); ++i)
    {
        vector<string>::const_iterator j = i->second.begin();
        cout << i->first << '\t';
        for (j; j != i->second.end(); ++j)
            cout << *j << " ";

        cout << endl;
    }   

    return 0;
}

Still have no idea why "while" loo[ didn't work.