Compilare: user.cpp: In instantiation of ‘matrix<N> solve(int, int, matrix<N>&, matrix<N>*, matrix<N>&) [with int N = 102]’: user.cpp:114:50: required from here user.cpp:77:19: warning: variable ‘tmp’ set but not used [-Wunused-but-set-variable] matrix<N> tmp = (P[idx]); ^ user.cpp: In instantiation of ‘matrix<N>& matrix<N>::operator=(const matrix<N>&) [with int N = 102]’: user.cpp:85:16: required from ‘matrix<N> exp(int, int, matrix<N>, matrix<N>*) [with int N = 102]’ user.cpp:112:23: required from here user.cpp:25:5: warning: no return statement in function returning non-void [-Wreturn-type] } ^