Compilare: user.cpp: In function ‘int main()’: user.cpp:38:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = x + 1; i <= 1 * scos.size(); ++i) ~~^~~~~~~~~~~~~~~~~~ user.cpp:14:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("undo2.in", "r", stdin); ^ user.cpp:15:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("undo2.out", "w", stdout); ^ user.cpp:17:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:20:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &comm, &x); ^