Compilare: user.cpp: In function ‘Node* new_empty_node()’: user.cpp:18:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int nr_app(Node*, char*)’: user.cpp:48:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int pref_lenght(Node*, char*, int)’: user.cpp:57:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:64:15: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(word); ^ /tmp/ccyRSTaS.o: In function `main': user.cpp:(.text.startup+0x4d): warning: the `gets' function is dangerous and should not be used.