Compilare: user.cpp: In function ‘void solve()’: user.cpp:133:27: warning: unused variable ‘old’ [-Wunused-variable] int i, x, y, ans = 0, old; ^ user.cpp: In member function ‘void myIfstream::advance()’: user.cpp:18:47: 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:167:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("ct.out", "w", stdout); ^ user.cpp: In constructor ‘myIfstream::myIfstream(const char*)’: user.cpp:27:43: 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); ^