Compilare: user.cpp: In function ‘int main()’: user.cpp:58:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<s.size()) ~^~~~~~~~~ user.cpp:71:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ok==0 and issemn(s[i])==0 and i!=s.size()) ~^~~~~~~~~~ user.cpp:77:32: warning: array subscript has type ‘char’ [-Wchar-subscripts] coeficient[s[i]]+=nr; ^ user.cpp:86:32: warning: array subscript has type ‘char’ [-Wchar-subscripts] coeficient[s[i]]-=nr; ^ user.cpp:110:13: warning: overflow in implicit constant conversion [-Woverflow] val[0]=-10000000000; ^~~~~~~~~~~ user.cpp:73:9: warning: ‘semn’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(semn=='+') ^~