Compilare: user.cpp: In function ‘void display_solution()’: user.cpp:46:26: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 2 has type ‘long long int’ [-Wformat=] printf("%lu\n", solution); ^ user.cpp: In function ‘long long int digit_found(int)’: user.cpp:100:6: warning: unused variable ‘numarator’ [-Wunused-variable] ull numarator = 1; ^ user.cpp:101:6: warning: unused variable ‘index’ [-Wunused-variable] int index = 0; ^ user.cpp: In function ‘void read_input()’: user.cpp:29:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &digit[i]); ^ user.cpp:33:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &k); ^ user.cpp: In function ‘int main()’: user.cpp:170:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qnp.in", "r", stdin); ^ user.cpp:171:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("qnp.out", "w", stdout); ^ user.cpp:173:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^