Compilare: main.cpp: In function 'int main()': main.cpp:17:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); i++ ){ ~~^~~~~~~~~~ main.cpp:23:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while( i < s.size() && ok == 0 && v.size()!=0 ){ ~~^~~~~~~~~~