Compilare: user.cpp: In function ‘void add(std::string&, int, trie*)’: user.cpp:42:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == a.size()){ ^ user.cpp: In function ‘int nr(std::string&, int, trie*)’: user.cpp:55:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == a.size()){ ^ user.cpp: In function ‘int tip(std::string&, int, trie*)’: user.cpp:62:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == a.size()){ ^ user.cpp: In function ‘int fct(std::string&, std::string&, int, trie*)’: user.cpp:69:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == a.size() || j==b.size()){ ^ user.cpp:69:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == a.size() || j==b.size()){ ^ user.cpp: In function ‘bool del(std::string&, int, trie*)’: user.cpp:76:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j == a.size()) --c->cnt; ^