Compilare: main.cpp: In function 'void push(trie*, int, std::__cxx11::string)': main.cpp:31:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(poz==ss.size()) ~~~^~~~~~~~~~~ main.cpp: In function 'int pop(trie*, int, std::__cxx11::string)': main.cpp:49:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(poz==ss.size()) ~~~^~~~~~~~~~~ main.cpp: In function 'int que(trie*, int, std::__cxx11::string)': main.cpp:69:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(poz==ss.size()) ~~~^~~~~~~~~~~ main.cpp: In function 'int pref(trie*, int, std::__cxx11::string)': main.cpp:80:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(poz==ss.size() || nod->child[ss[poz]-'a']==NULL) ~~~^~~~~~~~~~~