Compilare: main.cpp: In constructor 'usu::usu()': main.cpp:19:36: warning: passing NULL to non-pointer argument 2 of 'void* memset(void*, int, size_t)' [-Wconversion-null] memset(fiu,NULL,sizeof(fiu)); ^ main.cpp: In function 'void update(usu*, char*)': main.cpp:27:12: warning: NULL used in arithmetic [-Wpointer-arith] if(*s==NULL) //am terminat ^~~~ main.cpp:32:17: warning: array subscript has type 'char' [-Wchar-subscripts] int op=t1[*s]; ^ main.cpp: In function 'void solve(usu*, int)': main.cpp:57:22: warning: array subscript has type 'char' [-Wchar-subscripts] sol[n]=t2[nod->af]; ^ main.cpp:58:27: warning: array subscript has type 'char' [-Wchar-subscripts] solve(nod->fiu[nod->af],n+1); ^