Compilare: user.cpp: In function ‘void insert_word(TRIE*, int)’: user.cpp:24: warning: NULL used in arithmetic user.cpp: In function ‘bool delete_word(TRIE*, int)’: user.cpp:39: warning: NULL used in arithmetic user.cpp: In function ‘int NumberOfWords(TRIE*, int)’: user.cpp:57: warning: NULL used in arithmetic user.cpp: In function ‘int NumberOfPrefixes(TRIE*, int)’: user.cpp:66: warning: NULL used in arithmetic user.cpp: In function ‘int main()’: user.cpp:80: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result