c++ - Exception: STATUS_ACCESS_VIOLATION - pointer referencing -

i starting c++ (that after 10 years of java!). following examples stroupstrup book.

i put following code segments book.

#include <iostream> #include <map> #include <string> #include <iterator> using namespace std;  map<string, int>histogram; void record (const string &s) {     histogram[s]++; //record frequency of "s"     cout<<"recorded:"<<s<<" occurence = "<<histogram[s]<<"\n"; }  void print (const pair<const string, int>& r) {     cout<<r.first<<' '<<r.second<<'\n'; }  bool gt_42(const pair<const string, int>& r) {     return r.second>42; }  void f(map<string, int>& m) {     typedef map<string, int>::const_iterator mi;     mi = find_if(m.begin(), m.end(), gt_42);     cout<<i->first<<' '<<i->second; }  int main () {     istream_iterator<string> ii(cin);     istream_iterator<string> eos;     cout<<"input end\n";      for_each(ii, eos, record);      //typedef pair <string, int> string_int_pair;     //histogram.insert(string_int_pair("42", 1));     //histogram.insert(string_int_pair("44", 1));       //for_each(histogram.begin(), histogram.end(), print);     f(histogram);  } 

i error - exception: status_access_violation, think in referencing i->first, i->second, guess. can me out find out issue might be. if can suggest alternate c++ forums helpful well.

in void f(map<string, int>& m) function not check whether found element looking for, .e.g:

void f(map<string, int>& m) {     typedef map<string, int>::const_iterator mi;     mi = find_if(m.begin(), m.end(), gt_42);     if(i != m.end())        cout<<i->first<<' '<<i->second;     else        cout << "not found" << endl; } 

error occures when accesing i->first when i points "past end" of map container.