Question About Arrays inside functions

[SixDegrees]

You're passing your matrices by value. This results in a copy being made when the function is entered; all operations take place on those copies, not on the original matrices.

You need to pass them by reference

QVector<QVector<int> >& matrix, QVector<QVector<int> >& result

QVector<QVector<int> >& matrix, QVector<QVector<int> >& result

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(Note the ampersands.)

The C-style version works because you are effectively doing the same thing. You're passing in a pointer to the external arrays, not a copy. Pass-by-reference works exactly the same way, while providing some syntactic sugar by eliminating the need to dereference the arguments.