Compilare: user.cpp: In function ‘void expand(int)’: user.cpp:52:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < A[x].size(); i++) { ^ user.cpp: In function ‘void c(int&)’: user.cpp:35:38: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(s, 1, bufsz, stdin); ^ user.cpp:44:38: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(s, 1, bufsz, stdin); ^ user.cpp: In function ‘int main()’: user.cpp:66:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mine.in", "r", stdin); ^ user.cpp:67:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mine.out", "w", stdout); ^