Compilare: user.cpp: In function ‘int main()’: user.cpp:13:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(;i<s.size();++i) ^ user.cpp:19:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(s[st]==s[dr]&&dr<s.size()) --st,++dr; ^ user.cpp:20:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(dr==s.size()) {rst=st+1; i=s.size();} ^ user.cpp:23:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(s[st]==s[dr]&&dr<s.size()) --st,++dr; ^ user.cpp:24:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(dr==s.size()) {rst=st; i=s.size();} ^ user.cpp:26:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s.size();++i) g<<s[i]; ^