Compilare: user.cpp: In function ‘int main()’: user.cpp:43:10: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] v[k] = NULL; ^ user.cpp:32:9: warning: unused variable ‘cifra’ [-Wunused-variable] int cifra; ^ user.cpp:33:9: warning: unused variable ‘st’ [-Wunused-variable] int st = 0; ^ user.cpp:34:9: warning: unused variable ‘dr’ [-Wunused-variable] int dr = 0; ^ /tmp/ccv2RyhP.o: In function `main': user.cpp:(.text.startup+0x4e): warning: the `gets' function is dangerous and should not be used.