Compilare: user.cpp: In function ‘int main()’: user.cpp:52:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a.size();i++) ^ user.cpp:61:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a.size()/2;i++) ^ user.cpp: In function ‘bool div(int)’: user.cpp:28:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:57:17: warning: ‘nr’ may be used uninitialized in this function [-Wmaybe-uninitialized] nr++; ^