Compilare: main.cpp: In function 'int main()': main.cpp:41:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("lacat.in","r",stdin); ^ main.cpp:42:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("lacat.out","w",stdout); ^ main.cpp:45:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&n); ^