Compilare: main.cpp: In function 'void add(std::__cxx11::string)': main.cpp:46:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); i++){ ~^~~~~~~~~ main.cpp:53:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i==s.size()-1) v[cur].fin++; ~^~~~~~~~~~~~ main.cpp: In function 'void del(std::__cxx11::string)': main.cpp:60:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); i++){ ~^~~~~~~~~ main.cpp:63:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i==s.size()-1) v[cur].fin--; ~^~~~~~~~~~~~ main.cpp: In function 'int cont(std::__cxx11::string)': main.cpp:70:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); i++){ ~^~~~~~~~~ main.cpp:73:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i==s.size()-1) return v[cur].fin; ~^~~~~~~~~~~~ main.cpp: In function 'int pref(std::__cxx11::string)': main.cpp:80:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); i++){ ~^~~~~~~~~ main.cpp: In function 'int cont(std::__cxx11::string)': main.cpp:76:1: warning: control reaches end of non-void function [-Wreturn-type] } ^