Compilare: user.cpp: In function ‘int main()’: user.cpp:54:17: warning: NULL used in arithmetic [-Wpointer-arith] while(s[i]!=NULL){ ^ user.cpp:44:11: warning: unused variable ‘n’ [-Wunused-variable] long n,i=0,m,x,t; ^ user.cpp: In function ‘node* search_inchis(node*, long int)’: user.cpp:13:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘long int search_deschis(node*, long int)’: user.cpp:23:1: warning: control reaches end of non-void function [-Wreturn-type] } ^