Compilare: main.cpp: In function 'void add()': main.cpp:26:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp: In function 'void Delete()': main.cpp:42:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp: In function 'int count()': main.cpp:54:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) ~^~~~~~~~~