Compilare: user.cpp: In constructor ‘nrx_state_machine::trie::trie()’: user.cpp:334:27: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null] cnt_words = NULL; ^ user.cpp:335:30: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null] cnt_children = NULL; ^ user.cpp:336:33: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null] cnt_occurrences = NULL; ^ user.cpp: In member function ‘void nrx_state_machine::insert_word(nrx_state_machine::trie*, char*)’: user.cpp:348:31: warning: NULL used in arithmetic [-Wpointer-arith] if( *my_string == NULL ) { ^ user.cpp: In member function ‘bool nrx_state_machine::delete_word(nrx_state_machine::trie*, char*)’: user.cpp:364:31: warning: NULL used in arithmetic [-Wpointer-arith] if( *my_string == NULL ) node -> cnt_words --; else ^ user.cpp:368:57: warning: NULL used in arithmetic [-Wpointer-arith] if( node != root && node -> cnt_children == NULL && node -> cnt_words == NULL ) { ^ user.cpp:368:86: warning: NULL used in arithmetic [-Wpointer-arith] if( node != root && node -> cnt_children == NULL && node -> cnt_words == NULL ) { ^ user.cpp: In member function ‘int nrx_state_machine::count_word(nrx_state_machine::trie*, char*)’: user.cpp:378:31: warning: NULL used in arithmetic [-Wpointer-arith] if( *my_string == NULL ) ^ user.cpp: In member function ‘int nrx_state_machine::longest_prefix(nrx_state_machine::trie*, char*, int)’: user.cpp:389:31: warning: NULL used in arithmetic [-Wpointer-arith] if( *my_string == NULL ) ^ user.cpp: In member function ‘void nrx_state_machine::reset_machine(nrx_state_machine::trie*)’: user.cpp:400:37: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null] node -> cnt_occurrences = NULL; ^ user.cpp: In member function ‘void nrx_state_machine::build_occurrences(nrx_state_machine::trie*, char*)’: user.cpp:442:31: warning: NULL used in arithmetic [-Wpointer-arith] if( *my_string == NULL ) ^ user.cpp: In member function ‘void nrx_state_machine::build_partial_sum(nrx_state_machine::trie*)’: user.cpp:458:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < node -> front_node.size(); i ++ ) { ^ user.cpp: In member function ‘int nrx_state_machine::count_occurrences(nrx_state_machine::trie*, char*)’: user.cpp:468:31: warning: NULL used in arithmetic [-Wpointer-arith] if( *my_string == NULL ) ^ user.cpp: In instantiation of ‘nrx_segment_tree<Type>::tree_node::tree_node() [with Type = int]’: user.cpp:715:8: required from here