ASSERT failure in QList<T>::operator[]: "index out of range" file /usr/include/arm-linux-gnueabihf/qt5/QtCore/qlist.h

Question

I have recently been working on a project. When I attempt to run the project I get this error:

/ASSERT failure in QList<T>::operator[]: "index out of range", file /usr/include/arm-linux-gnueabihf/qt5/QtCore/qlist.h, line 487
The program has unexpectedly finished.

How I might go about tracking down the source of the problem?

I believe that the addition of this code is causing the error

startvaluexy = Client::straightxy;
qDebug() << "start value Received from server :" << startvaluexy;
QStringList xy = startvaluexy.split("|");

x = xy[2];

QString num1 = x;
int x = num1.toInt();

qDebug() << "start x value :" << x;

y = xy[3];

QString num2 = y;
int y = num2.toInt();

qDebug() << "start y value :" << y;

When this x = xy[2]; y = xy[3]; is taken out, then runs fine.

Answer 1

This is working fine.

startvaluexy = EchoClient::straightxy;
qDebug() << "start xy value Received from server :" << startvaluexy;
QStringList xy = startvaluexy.split("|");
int xySize = xy.size();
qDebug() << "start xy size :" << xySize;

if(xySize < 4){
    return false;
}

bool ok;
int x = xy[2].toInt(&ok);
if(!ok){
    return false;
}

int y = xy[3].toInt(&ok);
if(!ok){
    return false;
}

return true;