Compilare: user.cpp: In function ‘int main()’: user.cpp:36:31: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] z[strlen(z)-1]=NULL; ^ user.cpp:43:13: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] x[k]=NULL; ^ user.cpp:11:9: warning: variable ‘j’ set but not used [-Wunused-but-set-variable] int j; ^ user.cpp:12:15: warning: unused variable ‘q’ [-Wunused-variable] char *p, *q; ^