Undefined Reference to Class and functions

Question

Header file:

#include <string>

using namespace std;

struct word {
    int count;
    std::string w;
};

class WordAnalysis{
    private:
       int timesDoubled;
        word *words;
        int wordCount;
        int index;
        void doubleArrayAndAdd(std::string);
        bool checkIfCommonWord(std::string);
        void sortData();
    public:
        bool readDataFile(char*); //returns an error if file not opened
        int getWordCount();
        int getUniqueWordCount();
        int getArrayDoubling();
        void printCommonWords(int);
        WordAnalysis(int);
        ~WordAnalysis();
   };

Source file:

#include <iostream>
#include <fstream>
#include <sstream>
#include "WordAnalysis.h"

using namespace std;



void WordAnalysis::  doubleArrayAndAdd(std::string newWord){//double array length and add word
    bool checkCommon = checkIfCommonWord(newWord);
    int arrchecker=0;

    if(wordCount-1==index){//doubler
        timesDoubled++;
        wordCount = wordCount*2;

        word *list2 = new word [wordCount];
        for(int k=0;k<wordCount-1;k++){
            list2[k].count=0;
            list2[k].w="0";
        }

        for(int i=0;i<wordCount/2;i++){ //allocate old array to newly created f2 which was formerly pointing torwards the 4 array
            list2[i] = words[i];
        }

        delete []words;
        words = list2;
    }

    for(int j=0;j<wordCount;j++){//wordadder

        if(newWord==words[j].w){
            words[j].count++;
            j=wordCount;
            arrchecker=1;
        }
    }
    if(arrchecker==1){
        for(int i=0;i<wordCount-1;i++){
            if(words[i].w=="0"){
                words[i].w=newWord;
                words[i].count++;
            }
        }
        index++;
    }

}

bool WordAnalysis::  checkIfCommonWord(std::string word){
    bool check = false;
    string commonWords[]={"the", "you", "one", "be", "do", "all", "to", "at", "would", "of", "this", "there", "and", "but", "their", "a", "his", "what", "in", "by", "so", "that", "from", "up", "have", "they", "out", "i", "we", "if", "it", "say", "about", "for", "her", "who", "not", "she", "get", "on", "or", "which", "with", "an", "go", "he", "will", "me", "as", "my"};
    for(int i=0;i<51;i++){
        if(word==commonWords[i]){
            return true;
        }
    }
    if(check == false){
        return false;
    }
}

void WordAnalysis::  sortData(){
    word temp [1];
    for(int i=0;i<index-1;i++){
        for(int j=0;j<=index-i;j++){
            if(words[j].count > words[j+1].count){
                temp[0].count = words[j].count;
                temp[0].w = words[j].w;
                words[j].w=words[j+1].w;
                words[j].count=words[j+1].count;
                words[j+1].w=temp[0].w;
                words[j+1].count=temp[0].count;
            }
        }
    }
}

bool WordAnalysis::  readDataFile(char* filename){ //this opens and reads in file. returns false if error, argument is file name

    ifstream data(filename);

    if (data.is_open()){
    }
    else{
        return false;
    }

    string newWord;

    while(getline(data, newWord, '\n')){
        stringstream ss;

        ss<<newWord;

        while(getline(ss,newWord,' ')){
            doubleArrayAndAdd(newWord);
        }
    }

}

int WordAnalysis::  getWordCount(){//total non common words by summing counts from array words
    int sum=0;
    for(int i=0;i<index;i++){
        sum+=words[i].count;
    }
    cout<<"Total non-common words: "<<sum<<endl;
}

int WordAnalysis::  getUniqueWordCount(){
    cout<<"Unique non-common words: "<<index<<endl;
}

int WordAnalysis::  getArrayDoubling(){
    cout<<"Array doubled: "<<timesDoubled<<endl;
}

void WordAnalysis::  printCommonWords(int amount){
        for(int i=index+1;i>index-amount+1;i--){
        cout<<words[i].count<<" - "<<words[i].w<<endl;
    }
}

WordAnalysis:: WordAnalysis(int){
    for(int k=0;k<wordCount-1;k++){
            words[k].count=0;
            words[k].w="0";
        }

}

WordAnalysis:: ~WordAnalysis(){

}

The error is probably somewhere in source file with WordAnalysis:: WordAnalysis or something. I've looked through this website and while this is a common error, the errors are different from what I am having it seems.

We are not allowed to change the header file at all. But can change anything in source.

A few points (edited). The integer in WordAnalysis(int) is a number for the size of the array of structs declared in the header file. I didn't know where to create it but I thought that would be the best place with the int there.

It is also probably a quick error.