@Dummie1138 You might want to use QVector instead, which has resize. In Qt6 QList and QVector are the same anyway.
If not then you'll have to add them one by one e.g. like this, but it's not very efficient for a large n:

list.reserve(n);
std::fill_n(std::back_inserter(list), n, 0);

In regards to manually appending the list, I have the following code:

    for (int h = 0; h <= binMantissa.size(); h++){
        binMantissa.replace(h, 0);
    }

Is there a better way of doing it in Qt5 or is there a function that replaces all elements of a value?