Compilare: user.cpp: In function ‘int main()’: user.cpp:118:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < ans.size (); ++ i) ^ user.cpp:122:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; i < ans.size (); ++ i) { ^ user.cpp:135:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i < ans.size (); ++ i) { ^ user.cpp:83:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("johnie.out", "w", stdout); ^ user.cpp: In constructor ‘myIfstream::myIfstream(const char*)’: user.cpp:24:39: 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); ^ user.cpp: In member function ‘void myIfstream::advance()’: user.cpp:17:43: 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); ^