Compilare: user.cpp: In function ‘Node* new_empty_node()’: user.cpp:21:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int nr_appearance(Node*, char*)’: user.cpp:58:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int lenght_prefix(Node*, char*, int)’: user.cpp:69:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:76:19: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(word); ^ /tmp/ccycK9nO.o: In function `main': user.cpp:(.text.startup+0x41): warning: the `gets' function is dangerous and should not be used.