c++ program crashing because of if statment

My c++ program is crashing i think because of an if statement. I am using MinGW compiler and am given no errors. I have no idea as to why i am getting the error. The if statement in my generate function looks fine to me. Im comparing a string with an instance of a vector string.

here is the cpp code:

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <cstdlib>
#include <ctime>
#include "Insultgenerator_0hl14.h"

using namespace std;


FileException::FileException(const string& m) : message(m){}

string& FileException::what(){ return message;}

NumInsultsOutOfBounds::NumInsultsOutOfBounds(const string& m) : message(m){}

string& NumInsultsOutOfBounds::what(){ return message;}

InsultGenerator::InsultGenerator(const InsultGenerator& ) {};
InsultGenerator::InsultGenerator(){};

void InsultGenerator::initialize() {
    int cols(0);

    srand ( time(NULL));
    string words ;

    string filename("InsultsSource.txt");
    ifstream filetoread(filename.c_str());

    if(filetoread.fail()){
        throw FileException("File not read.");
    }
     while(filetoread >> words){

         if(cols==0){
            colA.push_back(words);
            cols++;
         } else if(cols==1){
            colB.push_back(words);
             cols++;
         }else{
             colC.push_back(words);
             cols= cols -2;
         }


     }


    //for (int i=0;i<50;i++){
    //  cout << "  "<< colA[i];
    //}
}






string InsultGenerator::talkToMe() const{
    string Thou = "Thou";

    string a= Thou + " " + colA[(rand()%50)] + " "  + colB[rand()%50] + " " + colC[rand()%50] +"!" ;

    //cout << a << endl;

    return a;
};//end talkToMe

vector<string> InsultGenerator::generate(const int num){

    if (num<0){
    throw NumInsultsOutOfBounds("You must be insulted at least once");
} else if (num >10000 ){
    throw NumInsultsOutOfBounds("You are being insulted too many times!");
}

    vector<string> insultList;
    string list;

     for(int i=0; i<num;i++ ){
         list = talkToMe();

        if(list != insultList[i]){
             //insultList.push_back(list);
             //cout << insultList[i]<< endl;
        }
     }



return insultList;
    };//end generate

    //int InsultGenerator::generateAndSave(const string filename, const int n) const{

    //};//end generateAndSave

int main(){
    InsultGenerator ig;
ig.initialize();
ig.talkToMe();
ig.generate(10);


    }

Here is the header file :

#ifndef INSULTGENERATOR_0HL14_H_
#define INSULTGENERATOR_0HL14_H_

#include <string>
#include <vector>

using namespace std;

class InsultGenerator{
public:
    InsultGenerator();
    InsultGenerator(const InsultGenerator&);
    void initialize() ;
    string talkToMe() const;
    vector<string> generate(const int) ;
    int generateAndSave (const string, const int) const;

private:
    vector<string> colA;
    vector<string> colB;
    vector<string> colC;
};

class FileException{
public:
    FileException(const string&);
    string& what();
private:
    string message;
};

class NumInsultsOutOfBounds{
public:
    NumInsultsOutOfBounds(const string &);
    string& what();
private:
    string message;
};

#endif