C++ Invalid Vector T Subscipt [Closed]

Question

void readGroups(ifstream &filein) {
vector<string> listOfStringTokens;
string tmpLine = "";
string tokens = "";

string courseCode, groupCode, groupName;
int minGroupSize = 0, maxGroupSize = 0;
int counter = 0;
while (filein.good()){

    getline(filein, tmpLine);
    istringstream iss(tmpLine);

    while (!iss.eof()){
        getline(iss, tokens, ';');
        listOfStringTokens.push_back(tokens);
    }
}
tmpLine = "";
tokens = "";
filein.close();

for (unsigned i = 0; i<listOfStringTokens.size(); i++){
    courseCode = listOfStringTokens.at(i);
    groupCode = listOfStringTokens.at(i+1);
    groupName = listOfStringTokens.at(i+2);
    minGroupSize = converter(listOfStringTokens.at(i+3), minGroupSize);
    maxGroupSize = converter(listOfStringTokens.at(i+4), maxGroupSize);

    cout << courseCode << "\t" << groupCode << "\t" << groupName << "\t"
         << minGroupSize << "\t" << maxGroupSize << "\t" << endl;
    i += 4;
}

}

int converter(string a, int b) {
stringstream convert;
convert << a;
convert >> b;

convert.str("");
convert.clear();

return b;

}

Hi everyone!

It is almost the first time for me using vectors and now i get stuck with this. The source of my problem is the increase of unsigned i variable in the .at() in the for loop as i brought it to light. However i must make it to get an appropriate output. So i need your help guys to make this code run perfect without modifie the structure of output.

Here's the output how it looks like:

xxxxxxxxx    xxxxxxx    xxxxxxxxxxxxxxxxxxxx    xx    xx
xxxxxxxxx    xxxxxxx    xxxxxxxxxxxxxxxxxxxx    xx    xx
xxxxxxxxx    xxxxxxx    xxxxxxxxxxxxxxxxxxxx    x     xx
invalid vector<T> subscript

Accepted Answer

You let i reach the largest number allowed to access the vector. The problem is you adding even more when calling "at".

Let's say that listOfStringTokens contains 12 Element. Imagine the last iteration: i<listOfStringTokens.size() is true and i is 11:

courseCode = listOfStringTokens.at(i);

This will work, because you access the index 11.

groupCode = listOfStringTokens.at(i+1);

This will not work, because i+1 yields an index that is out of bounds.

You also increment i in two different places:

for (unsigned i = 0; i<listOfStringTokens.size(); i++)

and here

i += 4;

This may cause you to lose oversight at a later point in time. Consider doing all incrementations in the first line.

C++ Invalid Vector T Subscipt [Closed]

Must Read

1 Answer

Elena Rostova