Compilare: user.cpp: In constructor ‘Node::Node(int&)’: user.cpp:39:40: warning: passing NULL to non-pointer argument 2 of ‘void* memset(void*, int, size_t)’ [-Wconversion-null] memset(sons, NULL, sizeof(sons)); ^ user.cpp: In function ‘void Insert(const string&, const int&)’: user.cpp:61:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < s.size() ; ++ i) { ^ user.cpp: In function ‘void BFs()’: user.cpp:74:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0 ; j < Q.size() ; ++ j) { ^