Compilare: user.cpp: In function ‘void sort_ins(int&, int, char*)’: user.cpp:16:44: warning: NULL used in arithmetic [-Wpointer-arith] if(j==nt or (strcmp(ing[j].nume, cuv)!=NULL)) ^~~~ user.cpp:24:38: warning: NULL used in arithmetic [-Wpointer-arith] else if(strcmp(ing[j].nume,cuv)==NULL) ^~~~ user.cpp: In function ‘int main()’: user.cpp:52:20: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] aux[k]=NULL; ^~~~