Compilare: main.cpp: In function 'void adaug(nod*&, std::__cxx11::string)': main.cpp:25:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < s.size(); i++ ) { ~~^~~~~~~~~~ main.cpp:32:36: 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:49:24: 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:69:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < s.size(); i++ ) ~~^~~~~~~~~~ main.cpp: In function 'void prefix(nod*&, std::__cxx11::string)': main.cpp:76:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int i = 0; i < s.size() && aux != NULL; i++ ) { ~~^~~~~~~~~~