'for' loop vs Qt's 'foreach' in C++

Which is better (or faster), a C++ for loop or the foreach operator provided by Qt? For example, the following condition

QList<QString> listofstrings;

Which is better?

foreach(QString str, listofstrings)
{
    //code
}

or

int count = listofstrings.count();
QString str = QString();
for(int i=0;i<count;i++)
{
    str = listofstrings.at(i);
    //Code
}