Compilare: user.cpp: In function ‘void backt(int)’: user.cpp:14:21: warning: unknown conversion type character 0xa in format [-Wformat=] printf("%\n"); ^ user.cpp: In function ‘int main()’: user.cpp:26:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("combinari.in","r",stdin); ^ user.cpp:27:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("combinari.out","w",stdout); ^ user.cpp:28:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&k); ^