Compilare: main.cpp: In function 'std::__cxx11::string simplifica(std::__cxx11::string)': main.cpp:28:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int f = 0 ; f < a.size() - 1 ; f ++) ~~^~~~~~~~~~~~~~ main.cpp: In function 'bool nextup(char*)': main.cpp:53:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int f = 0 ; f < simplificat.size() ; f ++) ~~^~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:98:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int f = 0 ; f < v.size() && f < 1000 ; f ++) ~~^~~~~~~~~~