Compilare: user.cpp: In function ‘void add(nod*, int)’: user.cpp:21:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos==cuv.size()) ~~~^~~~~~~~~~~~ user.cpp: In function ‘bool pop(nod*, int)’: user.cpp:35:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos==cuv.size()) ~~~^~~~~~~~~~~~ user.cpp: In function ‘int count_them(nod*, int)’: user.cpp:54:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos==cuv.size()) ~~~^~~~~~~~~~~~ user.cpp: In function ‘int largest_prefix(nod*, int)’: user.cpp:62:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pos==cuv.size()) ~~~^~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:70:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.in","r",stdin); ^ user.cpp:71:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.out","w",stdout); ^ user.cpp:74:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %s\n",&c,aux); ^