Using a vector function on a node member - c++

Question

I'm writing a program in C++ where I take in a line from a txt file and stick it into a vector<string> data that is within a struct (I'm making a linked list of each individual line). Technically I have a loop set up that will break up the words from the sentence I'm taking in, and pushing them into the vector one by one.
The issue I've ran into is when I try getting the vector size via
int size;
size = current->data.size();
Current being a node. I get both an implicit conversion warning and a "Thread 1: EXC_BAD_ACCESS (code=EXC_I386_GPFLT)".
Can anyone explain where I am going wrong? Is it just not possible to code something like that? Should I just create a counter variable to keep track of how many words are being placed into the vector? And what would be the best programming practice to go about achieving this?
Here is my main() file
#include <iostream>
#include <fstream>
#include "SkipGram.hpp"
using namespace std;
int main() {
string file;
ifstream inFile;
vector<string> sentence;
string line;
SkipGram control;
int skip;
int gram;
cout << "Please enter file name:\n";
cin >> file;
inFile.open(file);
while(!inFile.is_open()){ //makes sure we get a working file
cout << "Error reading in file. Please try again.";
cin >> file;
inFile.open(file);
}
cout << "Please enter how many words you want skipped and the amount of grams:";
cin >> skip >> gram;
while(!inFile.eof()){
getline(inFile, line);
control.convert(line);
}
control.skipGramFunc(skip, gram);
control.printSkipGram();
return 0;
}
Here is my .hpp file
#include <stdio.h>
#include <iostream>
#include <vector>
#include <string>
using namespace std;
class SkipGram{
public:
SkipGram();
void convert(string line);
void skipGramFunc(int skip, int gram);
void printSkipGram();
private:
typedef struct sentence{
vector<string> data;
vector<string> result;
int position;
sentence* next;
}* sentencePtr;
sentencePtr first;
sentencePtr current;
int amount;
};
Here is my .cpp file
#include "SkipGram.hpp"
using namespace std;
SkipGram::SkipGram(){
first = NULL;
current = NULL;
amount = 0;
}
void SkipGram::convert(string line){
// go word by word through sentence and create a vector out of it
// add into the sentence list
sentencePtr newSentence = new struct sentence;
if(first == NULL){
current = newSentence;
first = newSentence;
amount++;
newSentence->position = amount;
}else {
current = newSentence;
amount++;
newSentence->position = amount;
}
string word;
int length = line.length();
int i = 0;
int front = 0;
int temp;
while( i <= length){
temp = line.find(" ");
if( temp == -1){
break; //catches when sentence is done with
}
word = line.substr(front, temp);
newSentence->data.push_back(word);
temp++;
line = line.erase(front, temp);
} //END OF WHILE
}
void SkipGram::skipGramFunc(int skip, int gram){
// goes through word vector and rearranges them
if(gram == 1){
cout << "Need more than one gram!" << endl;
return;
}
if(skip == 0 || gram == 0){
cout << "Input cannot be 0!";
}
int size;
int temp;
int tempAmount = amount;
current = first;
skip++;
while( tempAmount != 0){ // while loop goes through all the sentences
size = current->data.size();
size = size - skip; // size here essentially becomes a marker to find out where to stop the loop
for(int i = 0; i < size; i++){ // for loop goes through all the words
for(int j = 0; j < gram; j++){ // this loop checks to see if we got the right number of grams
if(j == 0){ // are we on the first gram
current->result.push_back(current->data.at(i));
}else { // we want skipped gram
temp = i + skip;
current->result.push_back(current->data.at(temp));
} // END OF IF
}// END OF GRAM IF
current->result.push_back(",");
}//END OF WORD FOR
current = current->next;
tempAmount--;
}//END OF WHILE
}// END OF FUNCTION
void SkipGram::printSkipGram(){
int tempAmount = amount;
current = first;
while(tempAmount != 0){
int size = current->data.size();
for(int i = 0; i <= size; i++){
cout << current->data.at(i);
};
}//END OF WHILE
}

Answer 1

You never assign to next, but you do read it. Whereupon your program exhibits undefined behavior by way of accessing a value of uninitialized object.