Compilare: main.cpp: In function 'int main()': main.cpp:14:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp:19:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(st>=0&&dr<s.size()&&s[st]==s[dr]) ~~^~~~~~~~~ main.cpp:35:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp:40:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(st>=0&&dr<s.size()&&s[st]==s[dr]) ~~^~~~~~~~~