Compilare: user.cpp: In function ‘int main()’: user.cpp:87:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbsort.in","r",stdin); ^ user.cpp:88:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbsort.out","w",stdout); ^ user.cpp:90:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&n); ^ user.cpp:91:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(str); ^ /tmp/ccOmdmEw.o: In function `main': user.cpp:(.text.startup+0x74): warning: the `gets' function is dangerous and should not be used.