Compilare: user.cpp: In function ‘bool ok()’: user.cpp:104:9: warning: unused variable ‘ans’ [-Wunused-variable] int ans; ^ user.cpp: In function ‘void solve()’: user.cpp:113:9: warning: unused variable ‘step’ [-Wunused-variable] int step, st, dr, last; ^ user.cpp: In member function ‘void myIfstream::advance()’: user.cpp:19:43: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread (buffer, 1, SIZE, input); ^ user.cpp: In function ‘int main()’: user.cpp:146:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("rege2.out", "w", stdout); ^ user.cpp: In constructor ‘myIfstream::myIfstream(const char*)’: user.cpp:26:39: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread (buffer, 1, SIZE, input); ^