Compilare: user.cpp: In function ‘int valid(int)’: user.cpp:39:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < rep.size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:76:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spirala2.in", "r", stdin); ^ user.cpp:77:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spirala2.out", "w", stdout); ^ user.cpp:78:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &x); ^