Compilare: user.cpp: In function ‘void constr()’: user.cpp:17:32: warning: NULL used in arithmetic [-Wpointer-arith] for ( int i = 2 ; z[i] != NULL ; i ++ ) ^ user.cpp: In function ‘void cauta()’: user.cpp:30:30: warning: NULL used in arithmetic [-Wpointer-arith] for (int i = 1 ; s[i] != NULL ; i ++ ) ^ user.cpp: In function ‘int main()’: user.cpp:57:10: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[n+1]=NULL; ^ user.cpp:58:10: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] z[m+1]=NULL; ^