Compilare: user.cpp: In function ‘int main()’: user.cpp:26:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < number.length(); ++i) ~~^~~~~~~~~~~~~~~~~ user.cpp:47:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < digit_count.size() - 1; ++i) ~~^~~~~~~~~~~~~~~~~~~~~~~~ user.cpp:68:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < digit_count.size(); ++j) ~~^~~~~~~~~~~~~~~~~~~~ user.cpp:13:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("gap.in", "r", stdin); ^ user.cpp:14:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("gap.out", "w", stdout); ^