Compilare: main.cpp: In function 'void adaug(nod*&, std::__cxx11::string)': main.cpp:27:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < s.size(); i++ ) ~~^~~~~~~~~~ main.cpp:39:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int j = i + 1; j < s.size(); j++ ) ~~^~~~~~~~~~ main.cpp: In function 'void scoate(nod*&, std::__cxx11::string)': main.cpp:63:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < s.size(); i++ ) ~~^~~~~~~~~~ main.cpp: In function 'void afiseaza(nod*&, std::__cxx11::string)': main.cpp:95:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < s.size()&&aux!=NULL; i++ ) ~~^~~~~~~~~~ main.cpp: In function 'void prefix(nod*&, std::__cxx11::string)': main.cpp:106:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( ; i < s.size() && aux != NULL; i++ ) ~~^~~~~~~~~~ main.cpp:105:9: warning: unused variable 'cnt' [-Wunused-variable] int cnt = 0,i=0; ^~~