Compilare: main.cpp: In function 'int main()': main.cpp:70:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<gr[i].size(); j++) ~^~~~~~~~~~~~~ main.cpp:98:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<s.size(); i++) ~^~~~~~~~~ main.cpp: In function 'int det_elem_frecvent()': main.cpp:49:12: warning: 'elem' may be used uninitialized in this function [-Wmaybe-uninitialized] return elem; ^~~~ main.cpp: In function 'int main()': main.cpp:91:18: warning: 'elem' may be used uninitialized in this function [-Wmaybe-uninitialized] y.val=det_elem_frecvent(); ~~~~~^~~~~~~~~~~~~~~~~~~~