"String subscript out of range" error using vectors

Question

I am trying to pull characters from a specific column (in this case, 0) of a text file, and load them into a vector. The code seems to work ok, until it reaches the end, when I get a "string subscript out of range" error, and I do not know how to fix this. Does anyone know what I can do? Here is the relevant code.

class DTree
{
private:

    fstream newList;
    vector<string> classes;
public:
     DTree();
    ~DTree();

void loadAttributes();
};

void DTree::loadAttributes()
{ 

string line = "";
newList.open("newList.txt");
string attribute = "";
while(newList.good())
{
    getline(newList, line);

    attribute = line[0];
    classes.push_back(attribute);
}
}

Answer 1

You can also try something like

ifstream ifs("filename",ios::in);

string temp;
getline(ifs,temp)// Called as prime read

while(ifs)
{
    //Do the operations
    // ....

    temp.clear();
    getline(ifs,temp);
}
ifs.clear();
ifs.close();

This works for almost all kinds of files.You can replace getline(ifs,temp) by get() function or by >> operator based on your requirements.

Answer 2

Please try 'while(getline(newList, line)'

Refer here