Compilare: main.cpp: In function 'int main()': main.cpp:99:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); i++){ ~^~~~~~~~~ main.cpp:139:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); i++){ ~^~~~~~~~~