C++: Core Dump Exception

Question

I've successfully compiled this code, but when I get around to the last for loop in the main, I get a core dump handle_exception. How do I fix this?

main.cpp

#include <iostream>
#include <string>
#include <fstream>
#include <vector>
#include "DRSequence.h"
using namespace std;

vector <DRSequence> array;

int indexOfSequenceWithFirstWord(string word){
    for(unsigned int cnt=0;cnt<array.size();cnt++){
     DRSequence s = array[cnt];
     if(word.compare(s.firstWord())==0)
      return cnt;
    }
    return -1;

}


int main(int argc, char **argv) {

    cout << "Opening File:" <<  argv[1] << "\n";


    string in;
    ifstream inFile;
    inFile.open(argv[1]);
    if (!inFile) { cout << "Unable to open file"; exit(1); }

    unsigned int cnt = 0;
    DRSequence sequence;

    while (inFile >> in) {
     if(cnt % 2 == 0){
      int index = indexOfSequenceWithFirstWord(in);
      if(index<0){
       sequence.setFirstWord(in);
       array.push_back(sequence);
      }else
       sequence = array[index];

     }
     cnt++;
    }
    inFile.close();


    for(cnt=0;array.size();cnt++){
     DRSequence s = array[cnt];
     s.description();
    }

    return 0;
}

DRSquence.h

#include <iostream>
#include <string>
#include <vector>
using namespace std;

class DRSequence {
    string first;
    vector <DRSequence> array;
    int count;
  public:

    void description(){
     cout << first << "\n"; 
     for(unsigned int cnt=0;cnt < array.size(); cnt++){
      cout << "\t" << array[cnt].firstWord() << " " << array[cnt].countDegree() << "\n";
     }
    }

    void setFirstWord(string s1){
     first = s1;
    }
    string firstWord(){
     return first;
    }

    int countDegree(){
     return count;
    }

    void addSecondWord(string s){

    }


  private:

    int indexOfSequenceWithWord(string word){
     for(unsigned int cnt=0;cnt < array.size();cnt++){
      DRSequence s = array[cnt];
      if(word.compare(s.firstWord())==0)
       return cnt;
     }
     return -1;
        }


};

Answer 1

Your for-loop test is incorrect:

for(cnt=0;array.size();cnt++){

If the array has any elements in it, the condition array.size() will always evaluate to true and this will loop forever, where forever means "until array[cnt] is past the end of the array and you get an access violation."

You mean something more along the lines of:

for(cnt=0; cnt < array.size(); ++cnt) {