Compilare: user.cpp: In function ‘int main()’: user.cpp:96:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < len.size(); ++ i) { ^ user.cpp:44:17: warning: unused variable ‘lg’ [-Wunused-variable] double val, lg; ^ user.cpp:41:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("perm5.in", "r", stdin); ^ user.cpp:42:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("perm5.out", "w", stdout); ^ user.cpp:47:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^